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FOR THE PEOPLE FOR EDVCATION FOR SCIENCE
LIBRARY OF
THE AMERICAN MUSEUM OF
NATURAL HISTORY
on
PLATE VIT.
OLDHAMIA RADIATA
In the Collection of Edward Wood, Esq. F.G.S of Richmond, Yorkshire
S. J. Mackie Del i
| THE GEOLOGIST,
A POPULAR
MONTHLY MAGAZINE
GEOLOG Y.
EDITED BY S. J. MACKIE, F.G.S., F.S.A.
“ Geology, in the magnitude and sublimity of the objects of which it treats, undoubtedly ranks in the scale of the sciences next to Astronomy.’’—Herschel : Discourse on Study of Natural Philosophy.
LONDON: Pen OLDS & CO, 15 OLD BROAD STREET; SIMPKIN, MARSHALL, & CO., STATIONERS’ HALL COURT.
4
PREFACE.
Wira the new year I shall begin a new book, in the strong hope that more readers and more correspondents will join in aiding me in my earnest desire to popularize and to extend the noble science of geology without sacrificing, in any way, its proper dignity. The responsibility, to a conscientious mind, of a popular Magazine is not slight. Nothing once printed is innocuous or inert. ‘There is a corre- lation of human passions and intellect, as of physical force, and the effects of the printed sentence may be felt ineternity. The newspaper, with all its learning, its daily interest, the labour, skill, and cost of its production, passes with the day which gave it birth, but the magazine is bound into a volume, and may be read again months or years after- wards, and become, as it often does, the first course of instruction to younger minds. To make, then, this Magazine something more than a mere mirror of passing events, has been my aim and object; and the reward of all my anxiety and care to which I have hopefully looked forward, has been to see it not only a welcome monthly visitor, but a cherished friend.
To my many friends I take this opportunity of offering my warmest thanks, but to none am I so much indebted as I am to my true and valued friend, Mr. T. Rupert Jones. For the communications of my numerous correspondents I would also return special thanks, and I desire again to express a hope that the humblest geologist in this or any other land will never hesitate to communicate anything that he thinks a new fact or a discovery. No one at my hands will ever meet with a rebuff for his want of knowledge or skill, and it will ever be to those only who deserve it that I shall apply or sanction the sharp words of censure.
In the interval before our monthly intercourse is resumed, the most genial season, and warmest of all the year in friendship and spirit—if the coldest in temperature—will have passed over, with the celebration of those cherished festivities in which few, indeed, willingly fail to participate.
In the expressions of good wishes at this convivial season, none will be more sincere than those which I now offer to the many friends and acquaintances which my literary labours of the past year have gathered round me.
2. 4 S. J. MACKIE. Tachbrook-street, Pimlico, Dec. 1858.
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THE GEOLOGIST.
JANUARY 1, 1858.
HE GEOLOGIST, which this day makes its appearance as the
popular organ of a Science which has of late years advanced with gigantic strides, and which is daily attracting an increasing share of attention from all classes of society, enters upon an unoccupied field. Its object is to supply a deficiency in scientific periodical literature. We say this in spite of the sneer which has often been uttered to the effect that no new periodical was ever issued which did not profess “to supply a long felt want.” Of course new periodicals profess “to supply a want;” they are got up for that purpose; should those who bring them out think they are not “wanted,” it would be sheer folly to produce them. With regard to Tue Gerotoeist, there is abundant evidence that such a periodical is needed; evidence which rests not on our own judgment alone, but on the concurrent testimony of many eminently able and practical men, who have expressed their gratification at the announcement of a magazine, based upon the plan we have projected. We therefore venture to launch our first number with the full conviction that we are about to supply a work which will prove to be in a high degree useful.
In entering upon this undertaking, we desire to enlist the sympathy and aid of ali lovers of Geology. We need their assistance, and we here appeal to them to render it, and to do all in their power to further this effort to promote their faveurite Science. We have great confidence that in course of time, our magazine will flourish like a strong tree, but in its infancy it requires to be propped. We therefore ask all who wish to have
B
2 THE GEOLOGIST.
Geology properly represented, who desire to see erroneous notions regarding it eradicated, and correct ones established, who are anxious that it should hold the place im popular estimation which is its due, to come forward and exert them- selves in ensuring the success of Tue Gxrox1ocisrT; to help to make it valuable by furnishing contributions carefully selected from the stores of their knowledge; and to provide it with the sinews of war, without which no undertaking can succeed, by procuring for it as many subscribers as they can. If our friends will give us a good start we guarantee to run the race well; we are not without friends already; we have good friends.
“Our plot is a good plot as ever was laid; our friends true and “constant; a good plot, good friends, and full of expectation: an “excellent plot, very good friends.” *
We take this opportunity of thanking them, each and all, for their exertions in our behalf. For their sake as well as our own we ardently desire success. But though we have many good friends and true, we can find room for more ; we cannot have too many ; we want them everywhere. In every corner of the country where a labourer in the Geological field is to be found, there exists a man who has it in his power to uphold Tur Geroxoeist, and by upholding it, to foster Science. Again we say give help;—make our magazine known ;—encourage and recommend it. We do not expect to perfect our plan all at once; we come forth like an imsect emerging from its chrysalis case ;—presently we shall gain our full powers ;—one limb after another will unfold itself, and soon we shall spread our wings for vigorous flight. We shall stir up a taste for Geology, and add to the number of its votaries ;—we shall create readers,—learners,—workers. In this design we are not trenching upon the province of periodicals already established. It is to be borne in mind, that they are for the most part technical, abstruse and intelligible only to the well-read man of Science ;— they are intended for his use, and fulfil their mtention admirably. Our work, however, is popular ;—our pages are to contain such things as beginners can comprehend ;—our aim is to beget students, and to supply material for them to work with. We are not attempting to compete with existing magazines; we hope to
* Henry IVth.
THE GEOLOGIST. 3
see them flourish as they deserve. By creating more Geologists, we are likely to increase rather than diminish the number of their readers; we interfere with none, we plough in no man’s furrow, but break a new fallow for ourselves.
We are not so conceited about our workmanship as to think it perfect, and are not reluctant to believe that it may be improved, as it goes on; we are ready to listen to reasonable complaints, eager to receive useful hints and suggestions; we will do our utmost to discover and remove defects. We wish to make our magazine really good and useful; no personal caprice or individual interests shall be allowed to interfere with our efforts to make it worthy of the great science which it aspires to represent.
Geology is a noble science, and holds a dignified position amongst natural sciences. It is pursued as a study by a section of society which, though not large, is learned. It is wondered at, and enquired about by that larger section, who knowing next to nothing of its principles, meet with allusions to it in many of the books they read; who cannot help noticing as they walk about the country, that the earth is deposited in layers or strata; who see fossils dug out of Railway cuttings, or who stop to gaze with astonishment, blended with incredulity, at the restorations of uncouth antedilu- vian creatures in the gardens of the Crystal Palace. This science, elevating alike to the rational and moral constitution of man, affords to him, whose bent is to contemplate nature, a healthy intellectual occupation and a fruitful source of mental enjoy- ment; it treats of questions of the deepest interest to every reflecting mind; while its practical benefits are neither few nor unimportant. To the careful observer, who trains himself to a steady scrutiny of the things and circumstances amongst which he lives; who gazes at the heavens, not to indulge in empty musings upon the stars, but to reflect intelligently upon the laws which regulate their motions; who watches living beings, not to indulge in vain speculations as to the nature of vital force, but to ascertain the plan of their construction and vital actions, and the mutual relations of their functions; who, eschewing vague reveries, examines what he sees around him by the only test to be relied upon—the test of a sound experimental philosophy; who accus- toms himself to trace effects to their causes: searching fer sources
4 THE GEOLOGIST.
of error and rigidly excluding all he finds; to such a man— and is it not the duty of all of us to try to make ourselves such ?— Geology presents a never failing resource wherever he may be. It may be studied in every locality, is open alike to him whose lot lies in remote rural districts, and to the denizen of cities. The surface of the whole earth, and the operations constantly in pro- gress upon it, form the pages from which its lessons are learnt. Each cloud-capt mountain and fruitful valley; each rushing river and rippling brook; the surging ocean and the placid lake; the tide-worn sea beach and the well-tilled field, alike contribute to elucidate its mysteries. Not a lane, not a gravel-pit, not a quarry, or well, no summer’s scorching heat, no winter’s flood and frost, that does not furnish either the results and relics of bye-gone ages, or the key, by whose aid these may be deciphered, and their meaning interpreted. Every pebble, every grain of sand, has a wonderful history. The very dust of the ground we tread on is replete with food for thought.
If age is venerable, then do the subjects of which Geology treats command the highest veneration. The antiquary counts the years that have elapsed since the stately building, over whose ruin he ponders, was first raised towards heaven, but the Geologist can say,— Your old building is a mere stripling, compared with the stone it is built of; I will tell you of periods when that stone itself was being made; so lengthened, so remote, that the mind is lost in amazement, in considering them; if you love antiquities, follow me, and I will show you monuments and medals, ruins and relics, that will amply gratify your love for searching into the hidden past; I will disclose to you a tale of ancient epochs, so astounding as to make one quiver with emotion in listening to it, so marvellous as to fill the mind with unmixed reverence for the great Controller of events; the all-wise and Almighty Creator of the universe.”
This grand Science is intimately associated with several other natural sciences. Itis indebted to them, and theytoit. ‘The Chemist and Mineralogist have here an ample field for turning their studies to account; both of them gather from Geology stores of knowledge, and yield to it valuable information; the Zoologist is enlightened by it, and sheds upon it invaluable light; the
THE GEOLOGIST. 5
Botanist too in his department of Natural History both confers and reaps advantages. ‘The natural sciences are all mutually useful to each other; they are kindred branches of the one great tree of knowledge.
The practical benefits, to which we have made allusion, are set forth in detail in another part of our columns; they are many and great, and are seen in the daily useful application of Geological principles, in this and other countries.
Such is the Science we now aspire to promote. We come for- ward not arrogantly, as if we would dictate upon it, but with diffidence, lest we should not be able to do justice to so important a subject. We desire to elicit the results of the labours of Geologists and make them known to the world at large. We wish ‘to make Geology—in these days of Mechanics’ Institutes and Public Lectures—an object of popular enquiry and study. Surely we shall not fail through the lukewarmness of its votaries. In the name of Science we demand their co-operation. To them, to the Chemist, Mineralogist, Zoologist, and Botanist, and to all who desire to see knowledge of science diffused, we say: “Give us ‘your right hand, not as Lord Viscount Privilege did to Peter ‘Simple when he was a long way off the title, (extending towards ‘him just the tip of his forefinger) but give it as he would have ‘done to the heir of the family;—we don’t care for “the high ‘breeding ;”—let us have a brotherly greeting, and a hearty grip.’
THE EDITOR.
6 THE GEOLOGIST.
GEoLoGyY considered with reference to its Ur11t1ty AND PrRacticaL Errects, by the Rev. 8. B. Brodie, M.A.; F'.G.S.; Vice-President of the Warwickshire Naturalists’ Field Club.
Firty years ago Geology was in its infancy; there were but few who cultivated it as a Science. Museums were scarce and col- lections were only to be found here and there. If an unfortunate lover of nature was seen hammering in a stone quarry, he was generally supposed to be slightly demented. So rapid, however, has been the advance in general knowledge since that time, that the Geologist in these days pursues his researches unmolested ; the fre- quent visits to his favourite haunts cease to excite astonishment; indeed are rather regarded with favour and respect. It may now be safely affirmed, that most towns of any note have a well arranged Museum and there are usually a few scientific people in the neighbourhood. Colleges and schools have lectures on natural science ; and the universities are at last fully alive to the increasing demand for scientific knowledge, which may be turned to some practical account. The establishment of the Geological Survey, with its staff of able officers and an admirable Museum of Practical Geology ; and the spread of Field Clubs of natural history, in various counties, are undeniably important steps in the pursuit of science and form a bright era in its history. The student, therefore, has not the insuperable difficulties and drawbacks to contend with, in the present day, which he had to undergo formerly. It is certainly a step in the right direction, and a matter for congratulation, that Geology is more favourably regarded than it used to be, and we hope to see the day when it may be made a branch of education generally through- out the country. Still it is not to be denied that there are numbers of well meaning and estimable people, who not only underrate its utility and importance, but who reject most of its well-established facts, looking upon many of them as dangerous and visionary. This is not simply confined to the religious question respecting the original creation of the world and the periods of time of greater or less extent which all Geologists believe it to have occupied. But we have often heard asked “ Of what use is Geology, and what are
THE GEOLOGIST. 7
the practical results which might be expected from it ?” It therefore becomes desirable to answer this question clearly and decisively, and we think we shall be doing service to the cause of truth and sound philosophy if we draw attention to some of the most prominent features of the case.
Let us look to the practical results which Geology has accom- plished, and they certainly are not insignificant. They must satisfy every candid inquirer that its main object is not the mere breaking of stones or the collection of specimens. Even its theories, when based upon sound premises, are of great and essential service.
It has also a most extensive influence on nearly every depart- ment of science and art, and hence, of late, the study of Economic Geology has been more widely sought after and appreciated. In this department the practical fruits of the Science are most appa- rent, and the advantages arising from a correct knowledge of the internal structure of the earth are particularly impressed upon us, and every year may be expected to increase its popularity, as its utility becomes more widely known. The study of minerals and metals belongs, strictly speaking, to the Mineralogist, but the Geologist must be acquainted with the conclusions arrived at by the former. The direction of veins, the faults which affect them, and the probable richness or poverty of the strata in which the various ores occur, is the more immediate and legitimate work of the latter. The importance of an exact acquaintance with this portion of Geological research cannot be overrated, and those who really understand the difficulties to be overcome will best appre- ciate the benefits which this noble science has conferred.
This Science becomes of value in regard to the Carboniferous deposits, which, being generally deep-seated in the earth, and much disturbed by faults, are worked with considerable diffi- culty. The aid of the Geologist is of great service in deciding the direction of the strata, and the thickness, extent, and quality of the seams. The enormous consumption of coal, and its inestimable value for economical purposes, render its extent and ultimate exhaustion a momentous and very interesting question. Happily, this has been satisfactorily answered by many eminent Geologists, who have shewn that there
8 THE GEOLOGIST,
is coal enough yet to last for centuries, so that we need not feel any alarm on that head. Many fruitless attempts have been made in different parts of the country, to sink for coal where no one, with any knowledge of the nature of the surrounding Geological for- mations, would ever have dreamt of attempting it. If persons of competent authority had been consulted, no such errors could haye been committed, and many thousands of pounds would have been saved. Formerly, perhaps, it might have been in some instances difficult to find an able practical Geologist at hand, but now no such excuse can be urged, since the Geological Government Survey has been established on purpose to decide questions of difficulty as they arise, and to employ the efficient means at their command for the benefit of the public.
The phenomena of Springs is another important consideration, inasmuch as from them we derive our purest supply of water, the abundance and quality of which has everything to do with the sanitary condition of our large towns. Now, since the certainty of procuring a sufficient quantity of water depends upon the inclination and character of the various beds of sand, stone, or gravel through which the rain percolates, it is requisite that this should be correctly understood before wells are sunk or reservoirs made. To determine this is one of the especial and most serviceable labours of the Geologist. In illustration of this we may refer to an able paper by Mr. Prestwich, on the water-bearing strata in the London clay with reference to the water supply of the metropolis. .
In the selection of building materials a most necessary enquiry is “where can good, lasting building-stone be obtained?” The selection of the best for the purpose, is most essential, and can only ‘be effected by a thorough knowledge of the structure and properties of the rock from which it is to be taken. Oxford is a memorial of the choice of a defective stone, and other instances of a similar kind might be mentioned.
Of late years the application of geology to agriculture has assumed -
an importance it justly deserves, and as the productive or non- productive power of soils depends in most cases upon the different constituents of the rocks themselves, it is necessary to understand their mineralogical character as well as their chemical ingredients,
THE GEOLOGIST. oT)
Thus Professor Buckman, in a very interesting paper on the Cornbrash* in the neighbourhood of Cirencester, in Gloucester- shire, has shewn the varying value of three different brashy soils, belonging to the Cornbrash, Great oolite, and Inferior oolite respectively; the first of which yields the most abundant produce. He also points out how “a successful farmer near Cirencester had converted a ‘brash farm,’ (usually a term of reproach) into one of the most productive ones in the district.” Hence we may infer the great practical advantage of sufficient geological and chemical knowledge in all farming operations.
_ The drainage of lands is of no little consequence, both as regards the healthy condition of a neighbourhood, and the due cultivation of the soil. In general the deepest drains do not penetrate beyond the mere superficial deposits immediately overlaying the stratum on which they repose, though very often, where the surface soil is thin, the former is cut through to a greater or less extent. In either case, it comes within the province of the Geologist to determine the variable dip, thickness, and structure either of the surface soil or substratum, as it affects the question at issue.
Allusion here might reasonably be made to the valuable properties of rocks for some other economical purposes, such as lithography, lime, bricks, and roads ;+ in many cases they even form an available and excellent manure, some of which, as the Crag in Suffolk, is largely exported for this purpose.
Much of this has been perhaps discovered without the aid of Geology, but a good practical Geologist cannot fail to enlarge the sphere of observation, pointing out fresh localities, which his well-practised eye and scientific experience alone could have detected, besides giving other valuable information in relation to various points which would escape the notice of a superficial observer.
We have only briefly alluded to these subjects which relate more - * Proceedings of the Cotswold Naturalists’ Club, vol. i. 1853.
T In addition to these may be enumerated the cement stones in the London clay, and the manufacture of sulphuric acid from the pyrites contained in this formation; the value of ironstones generally both in the Inferior oolite and Lias, and in the Carboniferous series; the importance of the alum shale in the Lias at Whitby, and the manufacture of Carbonate of Magnesia from the Mountain limestone of Ireland.
Cc
10 THE GEOLOGIST.
especially to Economic Geology, but we hope we have said enough to show its value and importance, and to point out some at least of the practical results which it has produced, and which have no small influence on the welfare and prosperity of the country. There is, however, another consideration upon which we have not touched, viz., the training and culture given to the mind by all scientific pursuits. If Geology did no more than this, it would do a great deal, and would justly hold a high place as a branch of learning. But this is not all; Geology tells us of the history of God’s Creation in ages long since passed away, the records of which are only to be found in the rock masses which form the crust of the globe. Now, any thing which gives us a clearer insight into the works and ways of the Omnipotent Ruler of the universe carries with it a moral lesson and a divine philosophy which will have a practical effect upon a thoughtful and well- disciplined mind. We cannot decipher the testimony of the rocks without knowing something about the nature and character of the animals and plants which not only helped to form them, but, in most cases, actually compose them. But as these are generally merely the relics of a former world, we cannot read these records aright without some knowledge of existing forms of animal and vegetable life. We have here, therefore, an additional motive for Geological pursuits; for the study of natural history, whether past or present, is both useful and pleasurable.
While Geology thus has its uses and recreations, it demands laborious thought at home, as well as a quick eye and a ready hand in the field; for although it may not be necessary that the Geologist should be a master of Mineralogy, Chemistry, Botany, and Zoology in all its branches, yet he cannot safely remain ignorant of their general principles and facts, so far as they bear upon the history of the ancient world. It has already conferred many lasting benefits on mankind, and will, no doubt, as our knowledge is enlarged and error removed, add many more. False and dangerous theories have, indeed, been from time to time propounded, and occasional mistakes have been made, but the purest wisdom—the highest earthly knowledge—must sometimes be found wanting; this is inevitable in the lot of a finite being like man, and is not the fault of the particular science or study from
THE GEOLOGIST. 11
whence it seems to emanate. When the Geologist reasons from well-established facts, which are open to all who choose to grasp them, he need not be afraid of the ignorant prejudices and false accusations which have sometimes assailed him. ‘Truth is ever stronger than fiction, and must prevail; its voice will make itself heard in spite of opposition.
The Geologist stands upon a rock, and declares boldly whence
it has been derived, and what it contains, even though it may be far removed from its parent source; his marvellous revelations seem like the wonders of some fairy tale, so strange and yet so true, so startling and yet so imperishable. He touches the earth with the magician’s wand, and from it, at his bidding, spring forth mighty monsters of the deep, reptiles of gigantic dimensions, flying lizards of uncouth form, fish and shells, corals and sea plants, unlike their living congeners, but fulfilling a very important part in the history of the past, which would have been altogether lost and unknown except for the unlooked-for discoveries which Geology has of late years achieved. It is truly wonderful to see how from rude fragments of bone, mere remnants of a skeleton which once had life, the size and form, the structure and habits of the entire animal can be determined, and its restoration so far completed. _ These are some among the many marvels of the Science; more might be added, for every day brings forth new facts of greater or less importance, which may hereafter be turned to practical account, but enough, we think, has now been said (however imperfectly) to shew that Geology claims and deserves a place second only to Astronomy itself, and that its utility and attractiveness will rather increase than diminish, as long as its reasonings are kept within the bounds of a sober philosophy, and are carried on in a spirit of honest and generous rivalry. Truth is the motto which should be engraven on the hammer of the Geologist; it will then strike with a truer aim and better results, and his studies will not be selfish and unmeaning, but will produce the noblest ends which human learning can effect, namely, the glory of God, and the welfare of his fellow-creatures.
12 THE GEOLOGIST.
Asstract of a Notice of a new Genus or CrinoivEs, read before Section C. of the British Association for the advancement of Science, at Dublin, August 27th, 1857. Presented by Professor L. de Koninck, FP. G.S., of Liége; and Edward Wood, Esq., F. G. S., of Richmond, Yorkshire.
In the year 1854, when the Genus Woodocrinus was first described, a single species only had been found. Indications of others were impressed upon the slabs, the surfaces of which were almost com- posed of the remains. of the Crinoides. During the last three years great exertions have been made to discover all the fossils that this bed contains—and the gratifying result has been, that four or five new species have been added to that which was the type of the genus which Professor de Koninck described in a paper read before the Royal Society at Brussels, and figured in his work on the Carboniferous Crinoides.
The thin bed in which they have been found is of very limited area, being known in the district as the ‘Red bed’ of the Lead Miners, and is about the middle of the Yoredale Rocks of Professor Phillips’s ‘Mountain Limestone Geology of Yorkshire.’ The strata below and above it appear to be unfossiliferous. Its locality the Carboniferous Rocks on a moor in Swaledale, near Richmond, in Yorkshire.
These Crinoides are associated with the teeth of Petalodus Hastingii; and not the slightest trace of any other fossil has yet been found with them. They lie in the bed a confused mass of stems, calices and arms, twisted and interlaced in such a manner as would lead to the idea that they are the stranded remains of these creatures, torn from their beds, or driven from the zone of water where they lived; and that the locality in which they are found was not that which they inhabited. However that may be, the ocean, of which they were denizens, swarmed with them.
The newly-discovered species are by no means less interesting than that which was the first described, and they offer some peculiarities which tend to modify and to complete the character which has been assigned to the genus.
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THE GEOLOGIST. 13
’ The species at present known are, Woodocrinus macrodactylus —the type species—W. expansus, W. goniodactylus, W. decodac- tylus, and two others. There are imperfect remains of other species, and also of another new genus, but the specimens yet found are too imperfect to permit us to form a satisfactory opinion about them.
Of all the species Woodocrinus macrodactylus is by far the most common; not more than three or four good specimens of the others having been found among the accumulated debris of the type species.
The genus, which has been named after Mr. E. Wood, of Rich- mond, the discoverer of the whole series, is related to the genus Cyathocrinus of Miller, Taxocrinus of Phillips, Forbesocrinus of De Koninck—differing in having five subradial plates; while the first has only four, and the second and third none. It appears also to differ from Cyathocrinus in the mode by which the second radial is attached to the first radial plate, and from the two last in having the radial joints free, instead of being united laterally by inter- radial plates. The calix or head of this genus is cup-like; generally widely opened except in Woodocrinus decodactylus, which is narrow and elongated, like a champagne glass. Woodocrinus expansus slightly differs from the others in having the shelly plates which form the cup, larger and thicker.
Like all other Crinoides, the calix is composed of a series of plates, which in this genus are quite smooth, and form themselves into a star of five rays; the base contains five plates. Alternating with these are five large hexagonal plates, called ‘sub-radial ; which in their turn alternate with five pentagonal plates, called ‘radial ;) superposed upon which are five more radial plates, which are axillary, and from which spring two arms, which bifurcate from one to four times, according to the species. The basal and sub-radial plates are united by their lateral edges. The radial plates and arms are free.
In Woodocrinus macrodactylus the arms bifurcate but once, and. are 20 in number; they are thick, cylindrical, and in appearance not unlike the common earth-worm. In W. decodactylus they are long and slender, and bifurcate twice, making the number of rays 50. In W. expansus they bifurcate three or four times, and
14 THE GEOLOGIST.
the rays reach the number of 80, or sometimes 100. These rays are long, and very elegant; and the joints have a wedge-like form, and are so arranged that the thick end of the one corresponds with the thin end of the next. In W. goniodactylus the arms bifurcate so as to make a total of 50, while the joints differ from those of all other species in the angular formation of their dorsal aspect—the zigzag pattern formed by their peculiar style of articulations—and the thickening of the last axillary joint of each ray. The number of joints in each ray is never less than 4, and neyer more than 10. Each joint of these rays is furnished with a long, slender, many-jointed, flexible pinnule, which springs alternately from opposite sides of the arm, so as to make two rows. In W. goniodactylus these pinnules are more delicate than in the other species. The anal region, which is that part of the calyx not covered by the radial plates, is composed of small diversely-formed pieces; which are united above to the dome, and laterally to those plates from which the arms spring. In W. expansus these plates are fewer in number, and larger than in W. macrodactylus. The dome, which is the upper part of the skeleton, has not yet been found entire in this genus. A few plates of hexagonal and pentagonal form have been noticed; but neither its form nor size can be indicated with any certainty. It appears to be large; the plates are beautifully marked in a relief, with a star-like projection, not unlike the dog-tooth ornament which characterizes early English architecture.
The stems are composed of thin cylindrical joints, alternately larger and smaller, giving them a ring-like appearance. The thick- ness does not differ much in any of the species. The length is considerable, and very variable. But the special character of this stem is that, unlike the stem of all known crinoides, it is much thinner at the base than at the summit. No actual termina- tion can be said to have been discovered; but in all the species the stem is invariably tapering, so that the longer it is the thinner it becomes. This circumstance would lead us to imagine, that the creature floated freely in the water, and that the stems were used to balance it, and keep it upright while it floated. Should this fact be established, it will place this genus as a link between the free Comatula and the fixed Crinoid. It may, however, have had the
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THE GEOLOGIST. 15
power of fixing itself at will, as Dr. Buckland imagined to be the ease with the Pentacrinus of Lyme Regis; or the stems may have had a fixed point of attachment; while this form was adapted to give the utmost amount of flexibility, so as to rise and fall in a tidal sea. Im any case, whether floating or with the power of attaching and detaching themselves at will, or broken from their base, the fact that they were cast upon the beach when dead would account for the confusion with which they are thrown together, and for the absence of any fixed base to their stems, in case the last conjecture was found to be correct.
The remains of these creatures have been collected by hundreds, but, so far, only in this solitary district. Specimens are in most of the public and private Museums throughout England; thus prov- ing that our conclusions have not been arrived at hastily. Many of the specimens are in a beautiful state of preservation, as the series before the meeting will fully illustrate.
On Bone Bens and their characteristic Fossits. By W. S. Symonds, F.G.S., President of the Malvern Natural History Field Club.
“FourtTEEN years haye now elapsed,” says Sir R. Murchison, “since I proclaimed that the fishes of the Upper Ludlow Rock “appeared before Geologists for the first time as the most ancient “beings of their class; and all the subsequent researches in the “various parts of the world over which Silurian Rocks have “been found to extend, have failed to add to or modify this “ generalisation.”*
The Upper Ludlow fishes hold their position still, but time and experience have added somewhat to our knowledge, and whereas we formerly held that “BonE BEDs” were boundaries of Creation, —universal phenomena,—and that they marked out a certain horizon where whole tribes and races of animals were extin- guished, never to be renewed, it may be useful to Geologists to sum up shortly the evidence as it now stands, respecting these most interesting platforms of death.
* Siluria, p. 239,
16 THE GEOLOGIST.
There is not in all England more lovely scenery than that around the protruded Upper Silurian dome of Hagley Park, in the village of Bartestree, five miles S.E. of the old town of Hereford, nor am I aware of any locality where the Ludlow bone bed is more charged with the relics of dead fish and Crustaceans. Tt was here that my late friend, Mr. Scobie, obtained the most perfect claw of the “Pterygotus Problematicus,’—that extinct Silurian lobster,—yet known to science; here Mr. Strickland found the seeds of the first known land plant, a Lycopodium, or fossil club-moss; and the only time I could ever afford an hour’s work there, I obtained the finest spine of fhe Onchus Murchisoni, an Upper Silurian placoid fish, I have ever yet beheld; while, doubtless, the cabinets of the Geologists of Herefordshire are enriched with numerous specimens I have not seen. The members of the Woolhope Club can hardly allow so rich a bed to remain unexplored, more especially when the courteous owner of the land, Mr. Phillips, railed off the dome, and preserved it for their peeuliar examination and benefit.
To return to the organisms of the bone bed; it is a curious fact that, a few months after Mr. Strickland and Mr. Salter had described the Pterygotus of the Hagley dome, Mr. John Burrow should find the jaw-foot of the same animal in beds immensely lower in the Geologic scale, even in the Caradoc sandstones below Eastnor obelisk, on the flanks of the Malverns. Thus we have evidence that this Crustacean, or one of the same genus, lived in the Caradoc Ocean. Nor is this all; the Pterygoti are found in strata far higher than the Upper Ludlow bone bed; they swarm in the Tilestones of the Kington district, where it was discovered by Mr. Banks. It is there associated with its fellow-Crustaceans, Pterygotus Anglicanus and Himantopterus, with the Silurian fish, Onchus Murchisoni, the new forms of, Plectrodus, Cephalaspis ornatus, Auchenaspis Salteri, and last, though not least, with the Upper Silurian fossil, the little mollusc, Lingula cornea. We ascend considerably higher on the ladder of geologic history, and near Kidderminster we find grey tilestones passing upwards into true Cornstones; here Mr. Roberts detected the Pterygotus and Eurypterus buried in the same grave with those very charac- teristic Oxp Rep fishes Cephalaspis Lyellii, and Cephalaspis
THE GEOLOGIST. 27
Lloydii, and the seed vessels Parkia decipiens, so well known in the Old Red of Scotland. We have not done with the Eurypterus yet! At the very summit of the Cornstones, high up on Rowlestone Hill, near Abergavenny, the Eurypterus has again been found, and these beds are two thousand feet or more above the Kington Tilestones.*
Let us now turn to the evidence afforded by the fishes of this remote epoch. We have already seen that the Onchus Murchisoni was contemporaneous with the Crustaceans that existed with the Cornstone fishes, and we know that the towxst Old Red strata of Scotland, contain their wing-finned fishes, the Ptericthys, and that these beds are considerably lower than Scotch strata, which envelope the Cephalaspis Lyellii, &c., so that we may very fairly argue, that the Ptericthys was contemporaneous with the fishes of the Tilestones, and with the Onchus Murchisoni.
Now in Scotland, the Ptericthys has been found in the Yellow sandstones, at the summit of the Old Red, and the base of the Coal measures ; and near the Clee Hills, in Shropshire, Mr. Baxter, of Worcester detected a specimen in good preservation, in yellow sandstone, below the Mountain limestone, and the equivalent as regards age, of the Dura Den beds of Scotland, and the Cyclopteris sandstones of Ireland. Immediately above the Ptericthys beds of the Clees, the Mountain limestone is crammed with the palates and scales of Carboniferous fishes, and the yellow equivalent sandstones of Ireland and Scotland supply us with the Carboniferous fish, Holoptychius, and even the remains of Megalicthys. Indeed the Geologists of the Irish survey, with Mr. Jukes at their head, argue, and most fairly, that these yellow Cyclopteris sandstones are CarBonireRous rather than OLp RED deposits, nay, even that the so-called Old Red conglomerate is a Carboniferous conglomerate, forming the base of the Carboniferous deposits.
Here arise two interesting questions ; where can the Geologist point out a section in all our English district, where the “ brown stones” (Upper Cornstones) are to be seen passing conformably into the Old Red conglomerate ? and where, as regards Paleon-
* See Edinburgh New Phil. Journal, October, 1857, p. 257. D
18 THE GEOLOGIST.
tological evidence, are we to draw a line of demarcation m the Paleozoic Rocks ?
THE COMMON FOSSILS OF THE BRITISH ROCKS. By 8S. J. Mackin, Esq., F.G.S.; F.\S.A.; &c. &c.
CHAPTER I. The nature of Fosstxs and their value.
In a magazine devoted especially to the propagation of Geological knowledge, it seems no infringement of its space, no deterioration of its value, that some pains should be taken to aid the student in his early efforts, and to disperse broadcast some useful elementary information, which may proye to the mass at once a source of instruction and of enjoyment, and so, by clearing the road to future and higher studies, may foster a dawning taste, and ultimately prove the means of adding many volunteers, and not unlikely even some brilliant master-minds to the ranks of Geologists, that otherwise, deterred at the outset, might perhaps have turned their attention and talents to some more accessible, if not more congenial study.
Who does not feel some interest in the past history of this beau- tiful world—the scene of our labours and of our loves—of our sue- cesses and of our failures—the stage of our existence and the tomb of our dust ? If the animated creations of the past were dumb brute animals, still the earth was green and gay with trees, and plants and flowers—the hum of insects vibrated on the summer’s air, and the snows of winter covered the ancient lands with their hyemal mantle—the tides of ocean rose and fell, and the world went rolling on through time and space, through years and seasons. There were earthquakes then and blazing voleanos—and winds and storms—great waves and merry dancing ripples on the sea. Even more beautiful then, perhaps, in its wildness, was this beautiful world, e’er the voice of gladness had cheered it, or
THE GEOLOGIST. 19
the shadow of sorrow had passed over it,—e’er man was, and when it was God's alone!
How strange to look back into the past, how marvellous the changes, how wonderful the contrasts presented by the things which were and those which are. At one time we are regarding the myriads of small and crawling things of the primeval ocean’s deeps—at another contemplating enormous reptiles of whale-like size, sporting in the broad waters of a British Ganges—or we are turning in mental revision to the herds of gigantic oxen and deer browsing on verdant plains—the associates of the hairy mammoth, rhinoceros and hippopotamus—the prey of the cave bear and hyena; at one time contemplating the luxuriant foliage of a tropical clime, at another the floating icebergs and their stony burthens. Dream- like indeed are our visions of the past,—mysterious and solemn as our own being and existence, are the lessons which have been read in the dead language of the mountains. More unintelligible to the ignorant than alphabet of Greeks, or hieroglyphic of Egyptians, are the strange characters in which these lessons are recorded, but every letter is a volume, for these letters are fossils. Surely then, it is worth while asking, even if for the benefit of no one else than of those who have never thought about these things, —and a magazine, like a missionary, goes to strange and far distant places, and it may put the questions where they were little likely to have been put at all—What is a fossil, and what is its value ?
Under the term “fossils” are included not only the mineralized remains of organic substances, but also the impressions or casts of any such bodies,—of a footprint, a worm- track, or of a rain-drop, or a ripple-mark—of anything indeed which was once part of, or was in any way associated with the existence or conditions of any living object of a past creation, and not being actually a mere rock or stone, or in other words a mineral mass.
In Geology everything is complicated—elaborated, and every fossil, like an old house, bears marks of homely changes and associations, suggesting many a train of incidents and ideas; and, as the preservation of organic remains must be vastly diversified, so with the differences in the rocks themselves, there will be also
20 THE GEOLOGIST.
characteristic differences in the fossils. But more than this, where similar rocks have been subjected to different physical conditions, there also such differences will be manifested in the conservation of the fossil itself.
Any one who regards the aspect of a fossil will at once perceive that, although he cannot fail to recognise it as the remains of some organised being, a fragment or portion, it may be, of some fish, animal, plant, or shell, yet it is not really the actual bone, nor wood, nor shell which he sees, but these substances greatly altered from their former state, each having under- gone a process of transformation in its intimate structure or its composition, which, while the resemblance of the former shape has been perfectly retained, has in reality converted it into a something very different. Fossilization is not the mere impregnation of an object with mineral matter by its long continued entombment in the earth, but it is a process, or rather a collection of processes of far more wonderful character. Particle by particle of the ori- ginal organism may have been removed by the percolating waters— —slowly, and in the lapse of ages; and as slowly and as constantly, particle by particle has been replaced by particle after particle of some other* and very different element; thus the lime of the calea- reous shell has been often replaced by flint, or ordinary bone by ear- bonate of lime. Or, the dissolving waters may haye absorbed the shells and have left only a hollow cavity to mark their vacant
i 2 3 Lien. 1. Terebra Portlandica from the Portland Oolite. 1. Cast of Interior of the Shell. 2% Mould or Impression of the Exterior of the Shell. 3. The Shell itself.
* The scientific reader will be aware that in some rare instances the original condition of the organic substances appears to be retained.
-——
THE GEOLOGIST. 21
burial places. Such fossils are known as casts, where the rock has consolidated in their interiors; and as moulds or impressions where the external forms and ornamentation are indented in the clay or stone. There are many other processes of fossilization; by some of which the most exquisite tissues have been retained, and in others even distinct evidences of colour have been conserved.
On the slightest reflection it must be apparent that where, as is by no means uncommonly the case, an organic structure of much delicacy has been preserved in the soil, the process of preser- vation, must have been, at least in the first instance, if not posi- tively sudden, at least very rapid. Sometimes by an incrustation of the surface of the animal or plant soon after its death or its deposit in or upon the mud of the ancient seas, decomposition was for a time partially arrested, and the external parts thus saved from decay, while the internal have rotted away and left a cavity which may still remain, or which may have been filled up with sparry crystals, segregated from subterranean waters. At other times, as perhaps in the case of the chalk-flints, the inclosed organisms have been penetrated by the enveloping substance, the tenuity of which was often such as to have permitted its passage through the cracks and seams, and frequently even through the finest pores of the shells. So much then for “ What is a fossil ?”
Too many people still think Geology merely the art of collecting fossils and rocks and of getting names for them; and hundreds of those who go into a quarry, come out again with little other diffe- rence than that of being dirtier and dustier on their exit than on their entrance. The possession of a shell or even a lot of fossils is not sufficient for science; it may please the amateur or amuse the idle. Fossils are not to be hoarded as curiosities or rarities, but prized for their teachings. Go to the seaside and watch what takes place on shores which present the like conditions with the beds which have afforded your organic remains. Watch how the merry dancing waves, as they ebb away from the shore with playful dalliance, leave the impress of their last kisses on the sands ; watch how the rippled furrows are ridged and streaked by the breath of the gentle winds. See how the spray or the rain spatter out miniature craters, and the worms and crawling things make their tracks upon the sand; dig out the annelide and the
22 THE GEOLOGIST
shell-fish from their oosy homes, and note their positions in the earth; observe the zones of various plants and living things, and how they vary with the depth of tide or the kind of soil or sea-bed, and carry back your experiences to the quarry, and then you will perceive something, and as yet something only, of the value of a fossil.
On our shores are three zones, of materials, animality, and vegetation. The sea has sorted out the sand and mud from the heavier fragments,—which the restless waves have tossed along the strand and have rounded into boulders and pebbles,—and, between the tidal marks, has left the sand, while the finer particles have been carried into the region of, and below, low water.
So too, nature presents her three zones of animal and yegetable life; and, as the briny currents have carried the still finer particles of silt into yet lower depths and more profound abysses, so nature in the deeper waters presents other zones of created beings, with characters and habits equally suited to the varied conditions of their existence. The researches of modern naturalists have shown that not only are various forms of animals and vegetables circumscribed in their geographical distribution, but that they are also limited in their vertical range, or in other words, are prescribed within a certain depth of the sea, or a definite elevation of the land. Most organic remains, from the very means and circumstances of their preservation, are necessarily of marine origin, because terrestial or subaerial influences are more essentially destructive in their ordinary action ; and it is more rarely in comparison to the sub- marine operations, which are constantly at work, that those co-inci- dences happen by which the relics of the land, or even of the river or lake, are preserved.
Of actual depths of seas, the shell-fish or Mollusca, from the limited range of their locomotive powers, must be, next to alge, corals, bryozoa, and other fired forms, the most certain and definite in the evidence they afford; and thus it will be perceived, what an important bearing the study and knowledge of their habits, regions, and ordinary limits of depths will have in determining from the fossil species through their relations to their recent types, the conditions under which the strata,in which they are embalmed, were deposited, and the profundity of the pre-adamic seas or estuaries. As by the modifications and adaptations which are pro-
THE GEOLOGIST. 23
vided for the necessities of the inhabitants of the lake, river, or land, we can now assort, by means of their organization and structure, the fresh water tribes from the terrestrial or the marine, so by the like evidence in any of the past great periods of Geology, we can also, in the like manner determine those three important classes of depositary rocks, by their fossil shells alone.
Similar inferences are ever to be drawn of ancient conditions, from every other department of Nature,—from birds and fish, mammalia or reptiles, insects or plants,—all display alike the badges of their mundane offices while living; and, changed into stone, their lifeless fragments appear self-recordant of the events and phases of their existences. Each, like a dimmed half-faded photograph, seems tinged with the lights and shadows of the scenes in which its span of life was past.
When silently we rest beneath warm and glowing skies, or in easy chair, by winter hearth and cheerful fire, how many a scene comes rolling through the mind—a vast panorama moving on and on—presenting still some fresh familiar scene. How many thousand yards of canvas, how many miles of bright and beautiful painting, are rolled up in that mysterious scroll, the memory. How fresh and vigorous, as we unroll it in our reveries, come forth the prominent faces and features, the endeared or hated spots of bye-gone days, and how time and forgetfulness have scumbled down most of the harsher details into a mysterious and delightful haze, through which those minor groups are faintly seen. How too, by instinctive perceptiveness from what we know, do we enter into the scenes coiled up within the stony forms of plants, and bones, and shells; how curiously, piece by piece, do the fragments fit together, like the scattered tesselle of a Roman pavement, displaying in the intervals of color, outline, and vacuity, enough to manifest the tracery of the ancient floor, while as a nail, a peg, a bit of stained mortar, or acoin, complete the associations ;—imagination—memory’s sister,—re-builds the luxurious villa, and re-peoples it anew.
So from slight and apparently insignificant incidents are the great pictures of Geology elaborated and designed—and so does imagination in her reveries, not untruthfully and with a feeling very like remembrance, wander through the phases of those wonderful ages which have passed for ever away. Thus does even
24 THE GEOLOGIST.
the position in which a fossil is found tell its tale, and is not without importance in the interpretation of the earth’s history.
When from the fragments of the past creations you have discerned how to dispose the first faint lines of design, and by experience have so learned to fit them together as to comprehend or exhibit something of the beautiful tracery of those grand scenes in which Geology abounds,—you will have learned something yet more of the value of a fossil.
On the shores of the sea the waves in reckless confusion cast their spoils,—floating shells and wood, and the dead carcases of animals are mixed with boulders and rocks, and like the beaches and strands of to-day are the conglomerates and littoral deposits of the past—fragmentary or massive, organic or mineral, all in disorder, and contrasting with the deeper waters, where the
Lien. 2. Shells disposed by a current according to their forms.
feeble currents roll gently along the smaller shells and relics and carefully dispose them, with almost the regularity of a cemetery, in one direction according to their forms. True, under the influences of motion and gravitation, as the magnet to the pole, do they all point to the spot to which the current trends. Again, if in any of the ancient rocks we find the shells disposed throughout the thick- ness of the beds, at all levels, and in their normal manner—for all living shells have a natural position in the mud or sand, their close proximity not necessarily indicating immediate succession of depo- sits,—what should we infer? Shells do not rest indiscriminately on their hinges, nor their anterior nor posterior ends, but those with syphons project those organs upwards through the tubes of their burrows to inhale and exhale the aqueous fluid at once to them
THE GEOLOGIST.
Lian. 4, Recent Tellina tenuis in sandy mud.
26 THE GEOLOGIST.
Lian. 5. Recent Mussel (Mytilas edulis) moored by its byssus.
the means of respiration and the source of food. These live erect in the oose, others with plated gills, like the oyster or the spondylus, rest on one of their sides, while some like the mussel or the terebratula, are moored to the bottom by a byssus or set of natural cords. Each, however, has its normal position, and each thus by its position in the mud or rock, tells us, more or less distinctly, where it died, whether in its native home or at some distant spot. We know too by their being disposed throughout the stratum, without regard to special levels, that these molluscs lived and died naturally at that very place, that the sediments growing higher and higher,—film after film piled over other,—the young fry settled
Licn. 6. Shells at all levels in the strata of mud, shewing the gradual accumulation of sediment and the natural interment of the molluscs,
above the graves of their progenitors, and like them, in course of time were enveloped by the accumulating mud to be again sur- mounted by younger colonies who in their turn again succumbed. But where all on one line in their normal states, the fossil shells make one thin calcareous streak in the consolidated mud,
a =o vad
THE GEOLOGIST. Q7
Licn 7. Shells imbedded in a stratum of mud, all on one level, shewing the destruction of the molluscs by a catastrophe.
that narrow line at once speaks of the catastrophe—it is the mausoleum of young and old alike. A storm, a poisonous influ- ence, an inundation of mud or oose may equally have effected this ; but whatever was the cause the myriads were cut off at- once and suddenly.
One bed of rock may immediately overlie another, and yet a great interval may have occurred between them. The dis- tance of one bed from the other in time, may be a thousand years —or more. It may be ages,—or it may be but a day. The intimate particles of which they are composed may be silent upon this, the one may present a harder face or more consolidated constitution than the other, but of time they tell us nothing. What are days or years, minutes or hours, to the senseless particles drifted about by the changeful seas?’ Time was, however, to the perished shell- fish; they might not have measured it by months or years, by days or nights, but timed were their lives, and their species. They were not in their generations from the beginning until now, but they appeared and disappeared as the succession of the beds continued, and thus each great period of Geology had its creation of animated beings and vegetation, its fauna and flora distinct and appropriate—even as ours are now. One after another have these creations passed away, and in consequence of the suc- cessive upheavals and depressions of the land, the lines of level of different shells in a quarry may, nay, often do, note the demarcation of enormous periods—periods of mar- vellous ages—from each other. Nor do shell-fish only tell their tales of those remote times. The bright and scaly fish, decomposing on the ocean’s bed, has left a few and scattered scales, to mark its existence and decay; or a few isolated teeth, may be of sharks, or other predaceous fish, torn from their jaws by the struggling prey, are sufficient to record the ferocious instincts
28 THE GEOLOGIST.
of the ancient predatory tribes. In the Mansfeld slates thou- sands of fish, with scarce a scale displaced, may still (apparently) present in their contorted frames, the agonies in which their existences were terminated. The tree or plant may be yet erect— or its prostrate stem, or broken gnarly boughs may be eaten through and through by the sea-wood-worm (teredo)*—the one grew where it stands, the other, drifted over the wide ocean, speaks in its riddled substance, in silent eloquence of its wanderings.
He who carefully notes the position of the fossil, who records faithfully where it was found and how, is no mere collector; depend upon it he knows something still more of the value of a fossil.
One cannot begin everywhere at once, so something must be taken for granted. Among those things I must put upon the faith of the reader, are first, that this world is of very great antiquity ; millions, many thousands of millions—even myriads—of years old. And yet that it shall not be altogether on trust, we will draw again on one or two common fossils for just evidence enough to show that the strata are not of diluvial origin, but that time was taken to form them.
What do we see on our own shores where dead shells lie exposed on the surface of the mud? that worms (serpulz,) zoophytes, sponges, algee, and parasites of all descriptions encrust them with a little community of life.
Lien 8. Valve of Fossil oyster from the white chalk (of Dover,) with young oyster attached to the internal surface.
* The “ship-worm” of the present seas.
THE GEOLOGIST. 29
We figure a shell from the white chalk, one valve of an oyster with another smaller one attached to the internal surface. The first oyster must have lived and died, its animal substance must have been decomposed, or have been eaten out by the scavengers of the deep, ere the second could have attached itself to the inner surface of its valve, and this smaller one must have lived and grown from its almost microscopic state of fry to the size of the second oyster probably of two years’ growth—for the oysters of the chalk are small and thin. Suppose this: then it must have taken more than two years before the slowly-falling sediments of the Cretaceous Sea had accumulated to the extent of a few stout sheets of paper. Now the ordinary aggregate thickness of the three associated chalks, upper and lower white, and grey, is not much less than a thou- sand feet, and all this mass was formed at no greater maximum rate. The fossil shells and fish we find imbedded in its strata, of course lived and died in its waters—they were living-beings in those remote days. So self-evident does this fact seem,—although it was once stoutly discussed—that I have not dwelt upon it, nor shall I, as any doubts on this point will be swept away in the natural progress of our remarks. And yet the chalk is itself but a portion of the Cretaceous group or system of rocks, and that system but one amongst many systems formed at no quicker rate.
(To be continued.)
FOREIGN CORRESPONDENCE. By Dr. T. L. Puipson, or Paris.
Late Mortality amongst distinguished Geologists—Action of Water on Plutonic Rocks—Artificial Production of Minerals ; Aragonite formed in Steam Engines; Rubies and Sapphires—Oscillation of the North and South Coasts of France—The Sand of the Desert of Sahara— The Coryphodon—Newly discovered Foot-prints of Extinct Animals— Researches on the Flora of the Tertiary Formations.
Before entering upon the regular correspondence with which we hope to entertain our readers each successive month, by making known to them every new and important geological fact as it comes
30 THE GEOLOGIST.
to light in our part of the scientific world, we think it will not be without interest at the present moment, to cast a rapid glance over some of the later and more remarkable geological observations made on the continent during the year which has just hoses itself to a close.
It is with deep regret we must, in the first instance, inform our readers that the past year has been, for the science of geology, one of frequent and almost irreparable losses. One after another the names of some very eminent men have been erased from the list of the living.—While England deplores the death of Hugh Miller, Conybeare, Scoresby, and others whose reputations have not spread so widely, France feels how great is the loss she has just experi- enced by that of Constant Prevost, Dufrenoy, and D’Orbigny, who have opened more than one new and enlightened path in the obscure branches of their favourite science, and whose meritorious lives have not failed to excite a general admiration. Belgium has lost the eminent Dumont whose classifications of the Belgian strata and admirable geological maps have rendered his name immortal, and American science still mourns for the young and intrepid Dr. Kane, whose hazardous voyages of discovery and explorations of the Arctic Seas, have spread his fame far and wide. Germany has likewise suffered by the death of Dr. Lichtenstein, the learned director of the Geological Museum at Berlin, and the unrelenting hand of death, or rather, the accursed knife of a savage barbarian, has taken away from us the young and indefatigable African tra- veller, Dr. Vogel.
At one of the last meetings of the Congress of German Natu- ralists, it was proposed that an enormous erratic block of granite, measuring some six yards high, and from fifty to sixty yards in circumference, should be transformed into a monument to honour and perpetuate the memory of the illustrious Leopold Von Buch. The Congress received the proposition with acclamations of delight and immediately charged two of its members to superintend the operation. The eminent men whose names we have just men- tioned, do they not, one and all, deserve also their block of granite ?
In our idea nothing can be more interesting, and, at the same time, more important to geological science, than accurate investi-
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THE GEOLOGIST. 51
gation as to the manner in which minerals and rocks are formed and destroyed by nature.—Since the well known experiments of Sir James Hall, who transformed chalk into granular or saccharoid limestone in a heated and hermetically closed gun barrel; many philosophers have attempted to produce in their laboratories, the mineral productions found in nature. These attempts have been attended, in many cases, with perfect success, and the list, already rather considerable, of artificially formed minerals, is daily in- creasing.
Whilst M. Daubrée has been calling the attention of the Aca demy of Sciences to the rapidity and ease with which the Feldspar rocks undergo decomposition by the action of water, M. Becquerel has investigated the action of pressure and high temperatures in the production of artificial minerals.—Every one has remarked the prodigious action which water exercises upon minerals in general, but, however paradoxical the assertion may appear, nowhere can this action be rendered more palpable than when it is brought to bear upon the plutonic or eruptive rocks, such as basalt, granite, protogine, feldspar, &c., which, from their massive structure and hardness, would rather seem to be completely indestructible by an agent apparently so harmless as water. But these rocks contain, all of them, an alkaline silicate, soluble in water, and it is the separation and dissolution of this silicate that determines the decomposition and disaggregation of the rock. If we take, for instance, a piece of hard basalt, and grind it down in presence of water, the species of paste which is thus formed, presents, in a very short time, an alkaline reaction, rendered evident by test paper.—M. Daubrée has made a like experiment on a larger scale. He places in a barrel full of water, to which a movement of rotation is given, small fragments of quartz and feldspar. In a few hours the water contained in the barrel is found to have dissolved a considerable quantity of alkaline silicate.
M. Becquerel in order to obtain some idea of the chemical actions that have taken place in the sedimentary strata, at the time they were covered over, uplifted, and heated by the eruptive rocks, such as granite, porphyry, basalt, &c., has minutely studied the
32 THE GEOLOGIST.
influence of pressure and heat acting simultaneously upon different bodies whilst these bodies enter into chemical combination with one another. Nothing could be more simple than his mode of operating : Taking a thick glass tube, closed at one end, he places in it the substances intended to act upon each other, 7. ¢., to pro- duce the combination he desires. To procure a great pres- sure, he makes use of highly volatile substances, such as ether or bisulphide of carbon which he adds to the contents of the tube. The latter is then hermetically sealed and placed in an oven, to which, at will, a certain degree of heat (generally from 100 to 150 degrees centi-grade) can be given. In some cases Becquerel has added the action of a weak electric current to that exercised by heat and pressure in the experiments.
By operating in this manner he has lately obtained Malachite or carbonate of copper, exactly imitating the natural species; sulphide of silver, and Galena or sulphide of lead, have been obtained crystallised in thin lamine. Some beautiful samples of sulphide of copper were also produced in six-sided prisms, bearing the same angles and modifications, as those produced by nature herself. Protoxide of copper was obtained in fine octahedrons, and Aragonite or dimorphous carbonate of lime, in straight rectan- gular prisms so large as to permit an easy estimation of their angles.
Before quitting the subject of Becquerel’s experiments we would refer to an interesting fact, viz.: the formation of the last-named mineral species, in steam engines. The concretions formed in boilers of steam engines have been found, in cases where the incrustations were composed of carbonate of lime, to be almost always of that remarkable variety called Aragonite, distinguishable from the common carbonate or Iceland spar, not only by its pris- matic crystals, but also by their hardness which enables them to scratch those of the ordinary calcareous spar. It would seem from the foregoing observations, and from those formerly made by Gustav Rose, in Poggendorf’s Annales, that wherever carbonate of lime is precipitated at a high temperature, and under a certain degree of pressure, we have production of Aragonite.
THE GEOLOGIST. 33
M. Gaudin has likewise been very successful of late in the pro- duction of artificial minerals. He has given us a recipe for making sapphires in a few minutes, with hardly any trouble and at an extremely small expense. We know that the precious stones Corindon, Ruby, Sapphire, &c., are essentially formed of pure alumina, colored by very minute quantities of certain substances, the nature of which has not yet been perfectly determined. M. Gaudin, some time ago, obtained artificial rubies by melting alumina with a very small quantity of chromate of potash, but the process was rather a difficult one. He has lately made known an easier method by which he obtained an infinite number of minute erystals of alumina; these crystals were found to be, for the most part, transparent hexagonal tables, amongst which were seen smaller ones, quite red, and of a rhomboidal form. Most of them were exceedingly minute, and their forms could only be thoroughly examined by the aid of a microscope, but, since then crystals large enough to serve as pivots in watches, &c., have been ob- tained. The experiment just referred to furnishes us with another incontestable proof that the hard mineral substances presented to us in nature under crystalized forms, have been produced by the agency of heat, and have certainly not been deposited from water, as the crystals produced in our laboratories, from solutions, or like the beautiful calcareous spar which is forming every day under our eyes, in the grottos of limestone districts.
M. Tessier on presenting to the Paris Academy of Sciences, last October, a piece of petrified wood from a submerged forest on the west of Normandy, spoke of an interesting geological phenomenon which is taking place daily on the French coasts. It appears from his statements, that whilst the MediterraneanSea is slowly retiring from the south coast of France, rendering these shores yearly broader and broader by the new made land or muddy deposits it is leaving behind, the North Sea, on the contrary, is forcing its way slowly but surely on the north-western coasts, gradually en- croaching more and more upon the continent, and penetrating, in some places, to a considerable distance, into the neighbouring dry land. That this phenomenon has been at work for some time is proved by the fact that the ancient lighthouse of Boulogne, elevated during the reign of Caligula, and which was still standing in
F
34 THE GEOLOGIST.
the fifteenth century, has since disappeared and is now nowhere to be seen; the sea has long ago swept it away, and hidden beneath its waves the spot upon which it stood. We have nume- rous examples in geology of this encroachment and retiring of the sea on or from the coasts of different continents, and we shall doubtless have frequent occasion to refer to them in some of our future articles. The uplifting of certain banks of shells, the sink- ing or lowering of monuments erected near the sea coast, procure us ample grounds for investigating the effects and causes of these phenomena; and the slow oscillatory movements noticed on the coasts of Sweden, Norway, Sicily, Sardinia, Italy, New Holland, certain parts of America, &c., as well as the periodic, although irregularly alternating rise and fall of the water in the Caspian and Dead Seas, together with like phenomena already observed in the Coral Seas, show us, that without earthquakes, properly so called, the surface of the earth is capable of the same gentle and progressive oscillations as those which must have prevailed so generally in the earliest ages. One of the most curious oscilla- tions of maritime shores, is that which, according to Belpaire, is going on at the present time along the coast of Flanders. If we are to believe the eminent naturalist just named, the Flemish coast, from the mouth of the river Scheld to the town of Calais, is undergoing a species of oscillation, the axis of which motion appears to be situated near the little town of Nieuport. The land which extends from Nieuport to the coast of Holland, appears to be gradually sinking, whilst the coast line from Nieuport to Calais seems to rise slowly out of the sea. The extent of this oscillatory motion has not yet been determined with certitude.—* The eastern “coast of the Scandinavian peninsula,” says Humboldt, (*) “ has “ probably risen about 320 feet in 8,000 years. In 12,000 years, if “the movement be regular, parts of the bottom of the sea which “lie nearest the shores, and are in the present day covered by “nearly fifty fathoms of water, will come to the surface, and con- “stitute dry land. But what are such intervals of time, compared “to the length of the geognostic periods revealed to us in the “ stratified series of formations, and in the world of extinct and “varying organisms!” We may add with the same illustrious
(*) Cosmos, vol. 1, p. 802, Eng. Trans, by Otto.
THE GEOLOGIST. 35
author that the phenomena to which we have just alluded remind us of the instability of the present order of things, and the changes to which the outlines and configurations of continents are probably still subject at long intervals of time.
Our distinguished friend, Dr. Van den Corput, during a recent travel in Africa, has paid particular attention to the sand of the great Desert of Sahara. The samples he has examined were col- lected from the north-easterly regions of the great desert, which covers a tract of land of about 300,000 square leagues, ie., a superficies nearly three times that of the Mediterranean.* ‘This sand is so white and of so fine a grain, that one could easily mistake it for pulverized glass. — Ehrenberg once professed the opinion that the sand of Sahara was chiefly formed of the remains of hosts of microscopic animalculi, resembling those discovered in the calcareous formations on both shores of the Nile.—Van den Corput assures us that this opinion, to say the least, is extremely exaggerated. In the microscopical investigations to which he submitted the sand of Sahara he discovered neither Infusoria, Foraminifera, or Diatomacee, and very few, if any, organic or calca- reous remains. It appears formed, on the contrary, of extremely minute particles of pure quartz, having an irregular form and very sharp angles. The dimensions of the grains are much less than those of other similar deposits: Thus, whilst the grains of sand from the coast of the North Sea measure from 4-1000ths to 12-1000ths, and those of the tertiary beds, 8, 16, and 24-1000ths, the grains of sand from the great desert measure only from 1-1000th to 4-1000ths of an inch.—The author of these observations considers the Sahara sand as belonging to one of the most recent tertiary formations.
We will now turn our attention for a while to Paleontology.—It is not long since, that Professor Owen, from the examination of a single bone, or rather of a double tooth belonging to the lower jaw of an unknown animal, was bold enough to create a new genus of extinct pachyderms to which he gave the name of Coryphodon, —the tooth resembled somewhat that of a Tapir. The eminent palzontologist, M. Hebert, has since fully confirmed the generic distinction so sagaciously established by the illustrious English
* Compare Humboldt ; Views of Nature, Bohu’s edition, 1850, p, 89.
36 THE GEOLOGIST.
zoologist : Not only is the new genus Coryphodon now perfectly established as such, but. everything tends to prove that future researches will result in the discovery of intermediate forms, or genera of animals which are now wanting to fill up the gap existing between the genera Coryphodon and Lophiodon. M. Hébert has completed the entire dental system of the former, by the study of ninety teeth found in a more or less perfect state of preservation. Of these the canine teeth are more separated from the incisiva than in the Tapir; they are strong and very characteristic, resem- bling those of no other known animal living or fossil. It is now almost certain that there exist two species of Coryphodon: the first, called by Professor Owen, Coryphodon Eocenus, being more than twice as large as the second species, which M. Hébert has named Coryphodon Owenii. The latter of these two species was certainly a larger animal than the Indian Tapir, the former must therefore have been a most prodigious beast.
Whereas, in some instances, fossil remains and structures of organised beings are found perfectly preserved, even in their minutest details, in others the animal or plant has left nothing behind save a faimt impression of its tissues, engraven on the hard sandstone or argillaceous rock whilst still in a soft state ; one of the earliest discoveries of these impressions was made in Saxony, near Hildburghausen, by M. Kaup who found them on the surface of some slabs of variegated sandstone belonging to the Trias formation. M. Kaup and Alexander Von Humboldt regarded them as impressions of the feet of certain Mammalia to which the name Cheiratherium was given. This was rather a startling assertion, as no remains of Mammalia had ever been found in more ancient strata than the Tertiary.—Professor Owen, however, is of opinion that the foot prints in question were made by gigantic Batrachians.—Humboldt made known this important discovery to the Paris Academy of Sciences on the 17th of August, 1835. Shortly afterwards numerous tridactyle markings were ob- served in the Valley of the Connecticut, but these appeared to have been produced by biped animals, and were doubtless impres- sions left on the soft mud of the Trias by certain varieties of extinct birds, whereas the former were positively the marks of quadrupeds—whether Mammalia or not remains to be learnt. M.
THE GEOLOGIST. 37
Daubrée has just drawn our attention to a similar interesting dis- covery, which he has recently made in France. At Saint Valbert, between Plombiéres and Luxenil, there are some large quarries of Trias sandstone (variegated sandstone). It was in these quarries that the geologist we have just named, had the good luck to meet with impressions of the feet of quadrupeds in every respect similar to those formerly discovered at Hildburghausen, in Saxony. Un- derneath the thick strata of red sandstone, which is extracted for building, paving, &c., there exist thin layers of another sandstone, also of a reddish colour, but spotted with green, and alternating with layers of clay which show a like coloration. It was in these clay stratifications that M. Daubrée discovered the impressions we speak of: they were found on the surface of the beds of clay, where they join the superposed sandstone. No doubt exists as to the identity of the animal to which we owe these imprints in France, with the quadruped that produced them on the Trias formation in Saxony. At the side of the footprints of the larger feet were found also some much smaller, having only four toes, and reminding one of the feet of the Batrachian tribe. Not only the form of the feet, but the minutest details of the skin of the foot, are brought to light by a careful inspection of the foot-marks. After having thoroughly studied these and modelled, for the sake of comparison, some impressions of the feet of bears, kangaroos, crocodiles, lizards, &e.* M. Daubrée comes to the conclusion that the quadruped who has left these traces behind him in the Trias formation of Saint Valbert, must have belonged to the class of Mammalia. For our part, we feel more disposed however to adhere to Professor Owen's opinion alluded to above, at least until we shall have more evidence to the contrary than can be furnished by a mere foot-print.
The impressions left by animals who flourished on our planet in the earlier ages of the globe, teach us however some important geological lessons : They attest, in the first place, that the ground over which the animal walked was soft and damp, but nevertheless above water. But these sedimentary strata upon which the animal made his promenades, has since been covered by another deposit,
* These impressions were moulded in earth of the Trias formation, in which the ancient footmarks were found,
38 THE GEOLOGIST.
which has actually moulded itself upon the impression of the foot- prints left behind ; and then again by another deposit of the same nature as the first, which can only have been deposited from the sea.* Therefore the ground of which we speak, must first of all have been lifted above the water, that terrestrial animals could have walked upon it; it must then have sunk down again beneath the sea to receive the sedimentary deposits it reveals, and lastly, must have been uplifted again to attain the position in which we see it at the present day.
These phenomena which are revealed to us by the study of the formations of bygone ages, are therefore intimately connected with those oscillatory motions of the soil which we observe now-a-days on the sea-coasts in many parts of the world, and to which we have already had occasion to allude.
We will close our short exposé by a glance at the Flora of the Tertiary periods, to which our attention has been recently called by the appearance of two admirable works+ by the distinguished Professor Goeppert, of Breslau. In these works the learned author does not confine himself to the description of the fossil plants found in the tertiary beds of Schlossnitz and those of the Island of Java only; he moreover compares those with the whole known Flora of the tertiary formations in general, of which the different plants already amount to two thousand species.—This is also the first time that the fossil flora of tropical regions, situated far from Europe, have been compared with the tertiary flora of our own latitudes.
The principal families of which representatives have been found by Professor Goeppert in the Schlossnitz strata are as follows :-— Corylacez, of which there are twenty-eight species; Calicace, nine- teen; Betulaceex, eighteen ; Ulmacee, eleven ; Pinacee, six; Papil- lionacee, six ; Aceracee, seven ; Rosacee, four ; Juglandacee, three ; Combretacee, two; &c.—Professor Agassiz once remarked, if we are not mistaken, that no representatives of the family of Rosacee had ever been found fossil; it would appear from his statements
* This is rendered evident by the remains of marine shells, &c.
+ Die Tertiere Flora von Schlossnitz in 4to Leipzig 1855; and Die Tertiere Flora auf der Insel Java, in 4to Elberfeld, 1857,
THE GEOLOGIST. 39
- that these most useful plants, amongst which we find the apple, the pear, the medlar, the strawberry, the peach, the apricot, the almond, the plum, &c., &c., only made their appearance on the globe with the advent of man. We see, however, by the above, that four species of the Rosacee family have been detected in the Schlossnitz Tertiary by Professor Goeppert.
For the materials upon which Professor Goeppert has worked to form his tertiary flora of Java, he is indebted to M. Junghuhn, the ingenious naturalist to whom we owe a detailed description of the geology of this interesting island, published in Dutch and German. —The fossils of Java appear to belong to the Eocene period, ie., to the oldest Tertiary beds. A singular circumstance immediately strikes us as we examine these fossils ; the petrified trunks of trees that have been brought to light in the tertiary formations of Java are, withont exception, Dicotyledonous plants, whilst the forests that flourish at the present time on the island are composed of palms and arborescent ferns. However we must not attach too great an importance to this fact, for, the other fossils, 7.¢., those not petrified, found in these regions, seem to imply that it is merely an accidental occurrence.
The number of species collected by M. Junghuhn amounts only to thirty-nine, amongst which we find: six Palms, five Lauracea, five Celastraee, three Magnoliacee, three Corylocee (all belonging to the genus Quercus), three Pipracez, two plants of the genus Ficus, two Apocynacee, two Rhamnacee ; of the Musacee, Malpighiacee, Zingiberacee, Cornacee, and Ebenace, each one; we have also a species of Fungus, and three doubtful genera.
This small collection however is sufficient to rivet our attention on two striking facts : 1st. The plants of which it is composed are all new; 2nd. The families to which they belong still abound in Java. The vegetative system of this island has therefore not changed since the tertiary periods—which is contrary to what we observe in -Europe—the whole of the species discovered as yet and a few genera only, are alone found to be different.
40 THE GEOLOGIST.
REVIEW.
MEMORIALS, Scientific and Literary, of ANDREW CROSSE, the Electrician. London—Longman and Co., 1857.
The writer of this judicious and unpretending work is the widow of the now celebrated gentleman, whose biography she has so judiciously penned. ‘‘ Honour be to those, to whom Honour is due!”
Mrs, Crosse deserves the thanks of the reading, intelligent public, for the honest, modest book she has offered to the memory of her deceased husband.
It is not our intention to enter into the history of Mr. Crosse’s school exploits, his early taste for electricity and chemistry, his lightning-catching apparatus, or his dissection of thunder-clouds. Our aim in the pages of this journal will be rather to recommend good books, than to forestall them by extracts. We shall therefore merely point out certain Geological bearings developed by the Electrician’s experiments, and leave our readers to study the work for themselves.
Mr. Crosse was famous for the use he made of the electric current in the processes of crystallization. From his Voltaic Battery he produced “Two hundred varieties of minerals ’”—Sulphides of Lead, Iron, Copper, Silver, and Antimony, with many other compounds, made their appearance in his magic forge; also “Quartz and Chalcedony, with Carbonate of Strontia, Barytes and Lead.”
This part of the subject must ever be most interesting to the Geologist and Mineralogist. What problems may not these discoveries of the Electrician unfold, if legitimately applied to the question of Mineral Veins, and the much-argued history of Slaty Cleavage. Heat, we know, is developed by electricity, when the free passage of that power is impeded, and, surely it may have an enormous effect, while thus impeded, in changing the position of atoms, in segregation, compression, and dilatation. The Gatvanic Battery is far more likely to give the Geologist the clue to the history of Cleavage than the compression of mud layers in a tin case or a deal box. The development of the little mite ‘‘Acarus Crossii,” by electricity, caused a wonderful sensation some years ago, and we can remember when Mr. Crosse was taunted as “ Atheist,” ‘an impious philosopher,” the ‘‘disturber of the peace of families,” and, “a reviler of our holy religion.” After a time, the true revilers learned that there was no foundation for their attacks upon a character they could not appreciate, and, in justice, they should make themselves acquainted with the history of that good man, who was “neither an Atheist, nor a Materialist, nor a self-imagined Creator, but an humble and lowly reverencer of that great Being of whose laws his accusers seemed to have so lost sight.”
Men, who write tirades on subjects of which they are utterly and grossly ignorant, would do well to learn a lesson from the Life and Memorials of Andrew Crosse.
THE GEOLOGIST.
FEBRUARY, 1858.
Contributions to the Geology of Gloucestershire, intended chiefly for the use of Students. By the Rev. P. B. Bropiz, M.A., F.G.8., Vice- President of the Warwickshire Naturalists’ Field Club, and Honorary Secretary and Honorary Geological Curator of the Warwickshire Natural History Soccety.
We think it may prove useful and interesting to the geological student if, from time to time, we give a brief sketch of the Geology of some of the more famous localities in England, adding directions where to go, and how to work—which, to say the least, will be a great saving of time and labour, and enable those who are anxious to visit rich and instructive fields of research to make the most of perhaps only a brief holiday—a matter of no little moment in these days of almost unceasing toil.
The lovers of nature who live in the smoky atmosphere of great towns, shut up day after day in a close counting-house, enjoy a ramble amongst new or favourite haunts all the more on this account ; and it matters not whether they are naturalists, geologists, artists, or merely admirers of the picturesque—-the relish for their particular hobby is more keenly felt because it can be rarely indulged in, even if many difficulties stand in the way.
Few persons who have a scientific turn have unlimited time and means at their disposal; and, therefore, to the majority in such a case it is of some consequence to see as much as they can, and take the shortest route to their destination. The rapid and comparatively cheap means of transit afforded by the railway is equally available both for business and pleasure; but where science is the object, it is not always
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42 THE GEOLOGIST.
easy in a new country to find out the best and most productive places, and a few hints from any one who knows them well are invaluable.
With these introductory remarks, we proceed at once to the more immediate object of this paper. There is no county in the British Isles where the Geology is so yaried or interesting as Gloucestershire, associated as it is with diversified and beautiful scenery which would render it attractive to the mere casual observer. When it is recollected that many different Formations, from the Middle Oolite down to the lower Silurian system inclusive, can be studied with comparative ease, and a good suite of fossils collected from each stratum, the geologist will at once perceive the richness and extent of such a series, and the wide field of observation opened out before him. These different geological groups comprise a very extensive mass of rocks of vast bulk and thickness, of great value for economical purposes, and contain a distinct and variable fauna, which gives us an insight into the earth’s history in past times, from one of the earliest ages up to a much more recent period.
The neighbourhood of Cirencester is undoubtedly the best for ex- amining the upper portion of the Lower Oolite, the only member of the Middle being the Oxford clay, which has yielded an instructive set of fossils, and includes a band which appears to represent the Kelloways rock. The geological student will do well to devote a few days to the Cornbrash, Forest Marble, and Bradford clay, in connection with the Great Oolite, which may be reached within an easy distance of the town, and form the chief geological features of interest there. Though the Cornbrash is a comparatively thin bed, it makes a valuable soil to the agriculturist, and also yields a rich harvest of organic remains to the paizontologist. These consist chiefly of marine shells, some of which are peculiar to this Formation, while others occur also in the Inferior Oolite, and may be met with in the quarries near Cirencester, and also on the road to Fairford and Cricklade. Among the Brachiopoda there are several species of Terebratulz, and among the Echinodermata several forms of urchins, which are highly characteristic. The most instructive section may be seen at Kemble, on the line of the Great Western railway, where the Cornbrash, Forest Marble, Bradford clay, and Great Oolite are all present am stu, and exhibit an instructive fault, the Cornbrash on one side of it being brought down to a level with the Great Oolite on the other.
THE GEOLOGIST. 43
- Next to the Cornbrash the Forest Marble is the most important Forma-
tion in this district, which, although occupying hereabouts probably a larger area than the former, and, with its associated clay, thicker than the Cornbrash, is equally rich in fossils, and the thicker calcareous beds are of some value for economical purposes. There are several quarries opened in the neighbourhood of the Agricultural College, where many pretty specimens may be obtained. Of course the student will pay a visit to the excellent museum of the College, for which so much has been done by its present geological professor, Professor Buckman, and if he goes there first, he will observe what are the most character- istic fossils found in the Formations under review, and will very likely be able to procure many of them. In places, the Forest Marble contains traces of land plants, besides marine shells and corals, in which respect it resembles the Stonesfield slate, as also in its lithological structure. Many of the slabs quarried are very large, and are strongly ripple- marked, and, like similar strata deposited in shallow water, are fre- quently covered with worm tracks, and other curious markings not necessarily of organic origin.
Near Fairford, in an argillaceous stratum, probably connected with the Forest Marble,* numerous species of beautiful corals have been discovered, but the locality has been kept secret, and few collectors are acquainted with it. This, we think, is to be regretted; it is a sort of close-borough system, which should never be permitted among men of science, and we are satisfied that a liberal spirit, both in making known interesting localities for rare specimens, and a readiness to lend them when required, is the real mark of the philosopher, and most conducive to the interests of science.
The Bradford clay, which does not always accompany the Great Oolite in its range, is well displayed on the line of the Great Western railway near the Ackman-street station ; and, although not exceeding seven feet in thickness, is loaded with fossils, upwards of 200 species having been collected by Professor Buckman from this spot. Most of these are present in the Great Oolite also, but a few, perhaps, may be peculiar to it. One of its most striking organisms—the beautiful Apiocrinite, or pear-shaped Encrinite, does not occur here, though it occurs abundantly in the same stratum at Bradford, in Wiltshire; but there are plenty’ of pretty shells and corals to repay the collector.
* Or, perhaps, the Cornbrash. G2
44 THE GEOLOGIST.
We should now recommend him to take the train to the station nearest to Sapperton Tunnel, as this will enable him to examine the Fuller’s Earth which was cut through during the excavations for the tunnel, and which may still be seen on the spoil banks adjacent. We have not said much at present about two very important formations which lie between the Bradford clay and the Fuller’s Earth, viz., the Great Oolite and Stonesfield slate, because we propose to dwell more in detail upon them when we describe the district in Gloucestershire where they are most largely developed, and can be studied with most advantage. As the Bradford clay is intimately connected with the Great Oolite, so is the Fuller’s Earth with the Inferior; the majority of the fossils pre~- vailing in the Oolite below, and a few passing upwards into that above. It is very rarely that the argillaceous band appears 7m stfu, its presence being only indicated (like the upper lias), especially on some of the higher escarpments of the Cotswolds, by the soft, wet nature of the ground, and the bursting out of copious springs. <A few fossils, chiefly shells, have been obtained at Cubberly, near Cheltenham ; but Sapper- ton is the richest locality. Its thickness in this district averages from thirty to seventy feet, and the most abundant fossils are Modiola, Ostrea, and Terebratule. From this point the student should make the best of his way to Minchinhampton Common, where the Great Oolite has been long quarried, and from whence some of the finest and most beautiful of its fossils have been obtained. We should advise him by all means to pay a visit to the valuable and instructive collection made by Mr. Lycett at that village, to whom palzontologists are indebted for the discovery and investigation of many new forms of marine animal life (chiefly mollusks) which inhabited the sea during this portion of the Oolitic period.* Abundant and varied as these remains are, it is a remarkable fact that there are no traces of any higher order of animals, either terrestrial, fluviatile, or marine, which would seem to imply that land was far distant, although the sea was probably a shallow one and liable to strong and varying currents. The thickness of the whole of the Great Oolite in the district under review does not exceed 140 feet, the upper portion consisting of several beds of hard limestone and marl, containing the remnants, as it were, of a marine fauna, which abounds
* The majority of these are described and figured by Messrs. Lycett and Morris,
in the “Memoirs of the Paleeontographical Society,” Part [I1f., 1850, and Part IV., 1853.
THE GEOLOGIST. 45
in genera and species, both univalves and bivalves, in the lower division of this Formation. This latter forms the shelly oolite, locally de- nominated ‘‘ planking,” and constitutes the upper building stone, which is extremely rich in sea-shells, especially univalves, which here occur in great diversity, size, and abundance. Indeed, there is no other part of England where the Great Oolite is so prolific in fossils of this kind; and though much patience and skill are often required in extracting them, the labour is well repaid, and many a choice specimen added to the cabinet. The Geology of this neighbourhood is extremely interest- ing in other respects, from the striking physical features which it presents, owing to the numerous breaks which occur in the continuity of the strata, which not only expose many important sections of the strata, but also give rise to the picturesque and beautiful scenery for which this part of Gloucestershire is so justly celebrated. The vales of Brimscomb, Woodchester, Stroud, and Rodborough may be mentioned as among the most striking and attractive. In order to become well acquainted with the geological details of this part of the country, a longer residence would of course be required, and would be always remembered with pleasure; but those whose time is limited must be satisfied with a visit to Minchinhampton Common, and a walk through the valley of Rodborough, all of which may be accomplished in the course of a long summer’s day. This is one among the many advantages of Geological pursuits, that it affords healthful exercise for the body as well as food for the mind, so that it has a twofold advantage in this respect. There are probably few geologists who have not a keen appreciation of the beauties of nature, as well as of the wonders of creation. We strongly recommend a walk, hammer in hand, over the breezy Cotswolds; and if perchance, the student should have a day there with the Cotswold Club, he would obtain much assistance from the practical scientific knowledge which its working members possess of the county of which they may be justly proud.
We might have said a great deal more about the Great Oolite and its remarkable fossil contents; but, as our object is to aid the student by as simple an exposition of facts as the nature of the subject wiil permit, and to point out the most interesting localities over a widely-extended area, we must not dwell too long upon any one of these, but pass on to others equally instructive. The upper division of the Great Oolite may be seen again to the east of Cheltenham,
46 THE GEOLOGIST.
capping the higher ground, especially near Burford, Northleach, &e. In some respects it differs lithologically from the same Formation on Minchinhampton Common, and it is thicker in its extension eastwards. The top strata usually consist of beds of marl, which are more or less fossiliferous ; and the lower of white limestones, which are extensively quarried near Sherborne Park, above Burford: and, according to Mr. Hull, these limestones contain more fossils at a quarry where the Oxford and Shilton roads join, than anywhere else. Near Andoversford, about seven or eight miles east of Cheltenham, many fossils may also be procured in beds of rubbly, white Oolite. The usual fossils are shells and corals, belonging, however, to comparatively few genera, and presenting in this respect a strong contrast to the Great Oolite on the south.
The Forest Marble appears at Coln Rogers and near Aldsworth, about six miles south-east of Northleach, as well as near Burford, and the Cornbrash also near Shilton. We merely, however, mention this in case the student should like to compare them with. their equivalents near Cirencester ; for it often happens that even within a very few miles the divisions and sub-divisions of any given Formation present striking lithological differences—certain beds coming in, and others thinning out, which it is always necessary to note carefully, and which can only be done by a minute and accurate examination of every available section, and a close comparison of the zoological contents of each stratum.*
There is another and very important member of the Great Oolite with which it is intimately connected, and of which it forms an integral part, viz., the Stonesfield slate, to which we must now turn our attention. It forms the lower division of this Formation, and consists of a coarse, brown, fissile, ragstone, sometimes sandy and slaty, or passing into a shelly, oolitic freestone; and these characters are very variable over a considerable area in the Cotswolds. Formerly, there were several quarries worked at Sevenhampton Common, five miles east of Cheltenham, and are even now well worth a visit. The ragstone, which is a more compact slaty stone, often blue in the centre, is there
% We advise the student to get Mr. Hull’s valuable and interesting memoir on “The Geology of the Country round Cheltenham,” published by the Geological Survey, price 2s. 6d., where detailed sections are given, with copious lists of fossils, and ample details of every spot worth visiting.
THE GEOLOGIST. 47
overlaid by a few inches of clay, which contains many small shells, among which a small species of oyster (O. accuminata) is particularly prevalent. The ragstone is thirteen feet, and the very fissile slate, about five feet thick, immediately underlies it. The neighbourhood, however, of Naunton, Eyeford, and Temple Guiting affords the best sections, and numerous quarries are in constant work—as many as 120,000 slates being obtained during the season. At Northleach the slate becomes an oolitic freestone, mainly composed of small shells, more or less comminuted. This portion of the Great Oolite occupies a considerable extent in the eastern district of the Cotswolds, and may also be noticed at Notgrove, Miserden, and on the descent from Min- chinhampton to Brimscomb. Lithologically and zoologically it is identical with the slate at Stonesfield, in Oxfordshire, which has long been famous for its organic remains; indeed, it may be distinctly traced, with few interruptions, from Sevenhampton to Stonesfield. The slate itself, like the Minchinhampton Oolite, is extremely valuable for archi- tectural purposes, and forms a good and useful building stone. The young geologist, however, can see far more of it in Gloucestershire, where many sections are exposed at the surface ; while in Oxfordshire, it is worked underground, and the workings are reached by means of a shaft.
To the paleontologist the Stonesfield slate is particularly interesting, from the abundance and variety of its fossil contents; for here we have, for the first time in the oolitic group, the relics of Mammalia and land saurians, though occurring again at a much later interval, higher up, in the Purbeck and Wealden at the close of the system. The Lower Oolite group in the Cotswold Hills contains, as we have seen, little else but an assemblage of marine shells, which attest the condition of the ocean at that epoch. The Stonesfield slate, on the other hand, affords a remarkable exception—for shells are not very numerous, the character- istic fossils being land plants, and relics of fish and sauriaus, terrestrial and marine, chiefly bones, teeth, and jaws. Parts of Insects, wing covers, and bodies of beetles, and wings of dragon-flies, which doubtless formed the prey of the insectivorous Mammals of the period, are not unfrequently associated with the above. Hitherto, no traces of Mam- malia have been met with in Gloucestershire, but it is by no means improbable that they will be hereafter detected. A few jaws only of small opossum-like animals of this class have been discovered in Oxford-
48 THE GEOLOGIST.
shire, but it is quite possible that other and larger genera flourished in that part of the country which formed the then existing land. These were accompanied by a gigantic carnivorous reptile, the Mega- losaurus, which roamed at large amongst the tropical Palms, Zamia and Cycas, which constituted a portion of the oolitie flora.
Another singular flying lizard, called the Pterodactyl, uniting in itself the characters of several distinct groups, appears to have abounded at the same time.
The common fossils are the remains of land plants, which occur more or less throughout the slate, fronds of ferns and small fruits being the most prevalent. The shells associated with the above are entirely marine, and usually exist only in the form of casts. Two new beautiful species of Star-fish have been met with, the largest belonging to the recent genus Solaster. The latter is a single specimen, and was obtained by Lord Ducie from the quarries at Windrush, in whose collection it now is. He also possesses an entire fossil fish from the same place, the first one, in a perfect state, ever found in the Gloucester- shire oolites.
We have dwelt longer upon the fossil contents of the Stonesfield slate, because it affords a clearer insight into the geological history of its Formation, and the terrestrial conditions which prevailed. They were clearly very different to those of the higher zone which succeeded it, and yet, throughout the whole, the changes were often marked and variable—indicated not only by the lithological structure of the stone, but also by the character of the fossils.
We think the student must be interested in the details given above, and we are sure that a careful examination of the whole of the district, the geological features of which have been thus imperfectly described, will amply repay any time or labour spent upon it.
We hope, in our next article, to resume the subject, and to give a brief account of the Inferior Oolite and Lias in their turn.
[Since writing the above, Mr. Lycett’s monograph on ‘‘ The Cottes- wold Hills”’”* has appeared, and the student would do well to obtain a copy, as it gives him a most complete and admirable account of the country referred to in this paper, especially the southern part of it, with which Mr. Lycett is well acquainted. ]
* Piper and Stephenson, price 5s.
THE GEOLOGIST. 49
On the Geology of the Beaufort and Ebbw Vale District of the South Wales Coal-field. By Guorce Purtuirs Bevan, Esq., M.D., F.G.S.
Wirn the exception of the very able memoirs drawn out by Sir H. de la Beche, in the ‘‘ Geological Survey,”’ Vol. I, and the sections of the same survey, as compiled by Mr. David Williams, no coal-field has been so little described or worked out as that of the South Wales basin, Although the work of a master geologist, yet the very nature of these memoirs, describing the general arrangements of the rocks in the south- west of England, altogether precludes any attempt at minute geology, which, indeed, should mostly be supplied by local workers. Other coal-fields have been ably and intimately described, but this particular field only in very general terms. Why it should be so f know not, unless it is that only of late years its vast resources have been opened up, and that its many romantic vallies, teeming with beauty above and brimful of coal and mine beneath, have been made accessible either to the tourist or the mining adventurer. Every year, however, sees new railways opened in Monmouthshire and Glamorganshire ; and I have little doubt but that the completion of that magnificent work, the Crumlin viaduct, has done more than anything else to attract persons to that part of South Wales, either from a love of the beautiful, or the scientific interest attached to it. For the study of practical geology in its several aspects, this coal-field possesses many advantages, particu- larly in physical geology and the peculiar manner in which sections are obtained, owing to the nature of the ground. In the important branch of paleontology, also, it is by no means deficient ; for, at least in this district, plants of the coal, as well as shells, fresh water and marine fish-remains have been discovered most abundantly. I propose, therefore, to give a brief sketch of this portion of the field, feeling assured that it is by local and minute investigation that the truths of the first great principles are upheld, and any new difficulties solved. The greatest length of the South Wales coal-basin is from east to west, extending from Pontypool to Kidwelly, a distance of about seventy miles, while the greatest breadth is about twenty-five miles from Merthyr or Hiry ain to Cardiff. In this measurement I have excluded the Pem-
— .
50 THE GEOLOGIST.
brokeshire coal-field, as both differing a good deal from the other in arrangement of beds and quality of coal, and separated from it by a considerable interval of old red sandstone.
The basin is bounded on the north, east, and west by a pretty uniform belt of millstone grit and mountain limestone, and on the south by a rather intricate interlacement of old red, mountain limestone, permian, and lias. The greatest depth is stated to be near Neath, where the lowest strata are 700 fathoms below the outcrop of the upper ones in the hilly districts. The physical features are pretty much the same throughout the country, although the quality of coal varies exceedingly, it being on the Monmouthshire or north-east side of a good coking kind, while below Merthyr, and in the Glamorganshire vallies, it has taken the character of stone coal. The coal in the Aberdare valley has been taken in large quantities down to Cardiff, as being of the best and cleanest kind for the use of the steamers. Having furnished this general outline, let us look more closely at this district in particular. Like all the rest of the field, the country is here divided into a great many narrow parallel vallies, which run from the north belt of limestone towards the sea, and are separated from each other by long mountain ridges. If we ascend one of these ridges, say the Doman Vawr, between Ebbw Vale and Nantyglo, we shall see as fine an example of physical geology and beautiful scenery as can be well imagined. To the north is extended the dreary table-land of millstone grit, succeeded by the limestone escarpments of the Llangynider range; while, beyond them, are the old red sandstone mountains of the Daren and Penallt Mawr, from whence, in heavy prominence, stands out the isolated mass of grit and limestone of Pen Cerrig Calch. To the east are seen the outlines of the Sugar Loaf and Skyrrid, capped by their old red conglomerates, while in the interval between them are the far distant peaks of the Plutonic Malverns. To the west, peering over their humbler neigh- bours, are the Breconshire Beacons (2,862 feet), keeping grim watch over the old town of Brecon and the Vale of Usk, while still to the west the eye can trace the same bold outlines of the northern border running into Carmarthenshire. To the south glistens the Bristol Channel, backed up by the faint Mendips and the Devonian coasts of Minehead and Ilfracombe; while, from east to west, appear ridge after ridge of Pennant sandstone like waves of a large sea, only distinguishable from each other by the alternations of light and shade and the masses of
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THE GEOLOGIST. 51
smoke from the vallies, telling of the enormous population on the surface, and the inexhaustible wealth below.
As a good introduction to the coal-field, the pedestrian geologist can scarcely do better than start from Abergavenny, a tolerably-sized town on the Newport and Hereford Railway. He there finds himself in a valley of old red sandstone, looking up the Vale of Usk. ‘To the north of the valley is a line of mountains capped with old red conglomerates, as the Sugar Loaf and Skyrrid, from under which creep out here and there an abundant development of cornstones and brownstones; and, although but few of the fishes of that period have been discovered there, there is little doubt that they are as abundant as in the neighbouring county of Herefordshire. This Vale, like the parallel vallies in the coal-field, shows the enormous powers of the denuding force, which has scooped out the softer marls, leaving the harder conglomerates untouched.
To the south the eye glances along the line of escarpment of the carboniferous limestone, which, rising up from Pontypool, makes a rather sudden turn, of which the Blorenge Mountain forms the corner- stone, and runs tolerably due west. Near to Carmarthen the observer will see, during his walk along this range, several utilitarian signs, such as an inclined plane or the shaft of a pit, indicating the approach to a manufacturing district. About four miles from Aber- gavenny, the road suddenly leaves the Vale of Usk to enter the north limestone gorge of the Clydach. In this valley are situated the Llanelly ironworks, flanked on each side by steep hills, along the north side of which the road gradually ascends for another four miles.
The thickness of limestone at Llanelly and Llangattock, on the Mynydd Pengwern, is about 520 feet, and is of good quality, being much worked to supply the farmers. The lowest beds are the purest, and best for agricultural and smelting purposes. There are frequent sections to be met with along the whole line of country; the nearest to the Llanelly quarries are those of the Trefil, of enormous size, and worked in terraces, from whence the stone is brought to supply the Ebbw Vale works. The junction of the millstone grit with the limestone is well seen here, as boulders of grit frequently roll over the summit and mingle with the débris below; indeed, in a small cavern to the east of the quarry the wails are of limestone, while the roof is of grit. This cavern was turned to good account by some blacksmiths at the time of
52 THE GEOLOGIST.
the Chartist insurrection, in 1839, and used as a place for making pikes and other weapons. The following is the section displayed here, which I have obtained, with some others, through the kindness of Mr. Adams, the resident manager of the above works. It occupies about 450 feet :—
Light grey limestone.
Dark grey _ do.
Light do, do.
Brownish coloured limestone.
Calcareous shale or marl, containing shells. Dark coloured limestone.
Light blue do.
Light grey do.
Light blue do.
Dark do. do.
Calecareous shale.
White limestone. . Grey do.
Light blue do. Calcareous marl. Dark Blue limestone. Light blue do. Dark blue do. Light grey do. Dark grey = do. Calcareous shale. Light grey limestone. Grey do. Caleareous shale. Dark coloured limestone. Grey do.
These rocks are tolerably prolific in fossils (principally in the cal- careous shales) although not in very good preservation—viz., productus comoides, spirifer, terebratula, euomphalus, phanerotinus, lithodendron, zaphrentis, and other corals. The walk up the valley, following the bed of the Clydach, is, for those who prefer the scenery to the limestone sections, of the most romantic description—the waterfalls, especially that of the Pwl-y-ewm, will alone repay the pedestrian for his trouble. Having arrived at the head of the valley, a short walk over the inter- vening millstone grit lands us at Brynmawr. ‘The grit occupies a large area of table mountain, and is as boggy and unproductive as most mill- stone grits. It consists, in some places, of a quartzose conglomerate, and in others of coarse sandstone, glittering with mica.
THE GEOLOGIS?. 53
I append a section of the grit, or, as it is locally termed, Farewell Rock, an expressive name given by the collier, although, as will be seen, it is not quite destitute of coal seams occasionally :—
Section or 80 YARDs.
Sandstone.
Strong white sandstone.
Sandstone and argillaceous shale.
Sandstone.
Argillaceous shale.
Coal, four inches.
Sandstones and shale beds,
Coal, one foot six inches,
Blue Sandstone.
Brown do.
* Argillaceous shale, with small pins of Ironstone containing shells.
Strong grey sandstone.
Dark do. and argillaceous shale.
Dark grey sandstone.
Argillaceous shale.
Dark grey sandstone,
Light brown do.
Conglomerate, or plum-pudding stone.
Brynmawr is a large mining town, with a population of about 8,000, which has sprung up as a feeder to the important works of Nantyglo and Beaufort. It is placed very near the outcrop of the coal measures, and at the head of one of the parallel vallies which I mentioned before. The guardian hills on each side are composed of Pennant grit or sandstone, which is usually considered asa middle series, separating the upper from the lower coal measures. These rocks attain a great thickness, and are characterised by a thin roofing sandstone, in form and appearance very like the hollybush sandstone at Malvern, but covered with minute carbonaceous specks. ‘The beds are stratified very regularly, with but a slight dip, and presentsmall and confused traces of vegetation. According to Sir Henry de la Beche they were found in the following manner :—He considers the principal mass of sand to have been forced along the bottom by the pressure and movement of super-incumbent water, but
*To this layer I shall afterwards more particularly allude,
54 THE GLOLOGIST.
little having been thrown down in plane horizontal surfaces from mechanical suspension in the water. It is a kind of deposit, which, if the sand be readily supplied, may be effected in very shallow water, and hence, by continued subsidence, a very great thickness may be eventually obtained. The Pennant rocks are not abundant in coal seams in this portion of the basin, but at the Town Hill, at Swansea, according to Mr. Logan, there are at least twelve veins in these sandstones, which there attain the thickness of 2,125 feet. Indeed, the only seam at Ebbw Vale is the Troed-y-rhiw coal, two feet four inches thick. Locally, the small veins found in the rocks above the coal, as also those found in the millstone grit, are termed Rosser Veins. ;
I propose, in another paper, to describe the veritable coal seams, with their fossil contents.
On Fish Remains in the Yorkshire Coal Field, near Wakefield. Communicated by G. W.
Tue disposition of the coal measures is pretty geuerally known by most persons who have paid any attention to the science of Geology.
It will not, therefore, be necessary for me to describe their position or the place they occupy; undoubtedly they are of very ancient origin, being nearly allied to the old red sandstone, amongst which some of the fossils, or rather similar fossils, have been found, which I am about to describe.
Hugh Miller is the great authority regarding the old red sandstone deposits; no man laboured here with more assiduity than he, and is is my regret that I have not, as yet, informed myself more as to his labours. His recent posthumous work, the ‘‘ Testimony of the Rocks,” alludes to some fish remains which Scotland has produced; but Professor Agassiz is still more eminent as it regards this interesting class of fossils.
I said interesting, for I had no conception that fish remains could have been rendered so remarkable, and this may be owing to the delicate and soft nature of the mud in which they have been laid. I cannot imagine
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THE GEOLOGIST. 55
that my readers should be so captivated with these remains as myself, for there is a peculiar interest felt by all those who conduce to any new discovery ; and the more any science is studied the more fascinating it becomes, particularly if we have been led into it by an intimate know- ledge of its mysteries from actual observation. Having had no guide amid some of the labyrinths in which I found myself involved, I have been led to mark my footsteps more carefully and studiously, and it is only by such careful procedure that we may expect to arrive at any satisfactory conclusions.
In the year 1839 Mr. Teale, an eminent surgeon and naturalist of Leeds, read a paper before the Yorkshire Geological and Polytechnic Society on the ‘identification of strata by the remains of fish contained in the car- boniferous system of the Yorkshire coal fields. He concluded that the Middleton bed, about five miles from Wakefield, was not identical with the Lofhouse Seam, but that a thin band of imperfect coal was identical with the Halifax beds, and he came to this conclusion because they both contained a bivalve shell of the Pecten character. He endeavoured to stimulate geologists and coal-owners to a further ex- amination of the fish coal strata, but I do not find that any further discoveries have been made since that period, with the exception of what I am about to relate.
It may be thought by some that I am going to establish some little renown for my own observations, but facts may be allowed publicity in a matter which concerns the geologist and naturalist. About the period, or perhaps a little before the time Mr. Teale read his paper to the Society, my attention had been led to a pit near Stanley, about a mile or more from Wakefield, near to which I found, on the embankment formed by the material thrown up in sinking the shaft, some indications of the fish structure, and was so fortunate as to find a scale or two and a tooth: from the small amount of material through which the shaft had been sunk, I was unable to collect much, but a few small specimens of bone were added to my scanty stock. My attention was, however, I may say happily directed this year to the similarity of material previously found to a more considerable portion thrown up and exposed to the day in the construction of the Leeds, Wakefield, and Bradford railway, and on further examination [ found certain indications of fish remains ; but I had then no idea of the field now opened, or about to be opened to view. In my first attempt this year I was gratified in finding
56 THE GEOLOGIST.
some scales of fish of a very minute character, with numerous bivalve fresh-water shells of the unio genus; I had not proceeded far, however, before I found new specimens of scales which I had never before seen, and it was not long before [ enumerated scales of several distinct characters, some finely enamelled, and fish-teeth of three or four different kinds. After a few weeks’ labour in this (to me) interesting field of research I obtained a jaw of a minute fish, very perfect, with six or seven teeth attached, and also a fine portion of a large jaw with three large teeth, which specimens were exhibited by my friend, Mr. Tootal, at alate gathering of the Yorkshire Natural History Society, at the hospitable mansion of Edward Wood, Esq., at Richmond, in this county, and there excited considerable interest.
The bed containing these fossils is exposed to view about a mile and-a-half to the north of the town of Wakefield, and is found dipping to the south-east in the direction of Stanley and St. John’s Church; in all probability it underlies the whole town, and possibly continues for many miles in extent. The thickness of the true coal immediate is only four or five inches, and it underlies the bed containing the organic remains, which bed is composed of a hard kind of splintery dark shale combined with a mixture of imperfect coal shale in layers, which easily yield to the hammer. It must be understood that the bed is of two kinds, one wherein the fracture is brittle and uncertain, the other where the cleavage occurs in layers of a more certain and determinate character, and yields easily to a blow given; the two combined are about two feet in thickness. Both above and below the beds is found the usual bind of a soapy texture, so common in the coal measures, and of a whitish or grey leaden colour. The probability is, that at some earlier period of this earth’s history, the bed alluded to was a deposit from some fresh-water lake, analogous, it may be, to some of the American lakes, wherein have sported a variety of fish chiefly of the Ganoid order. The scales of many exceed an inch square, and are covered with a fine- coated enamel, with very minute pores—for instance, the Megalicthys Hibbertii; others exhibit a rotundity of shape (the Holoptychius Giganteus) with beautiful markings on the under surface, which the softness of the bed and the extreme fineness of its composition tend greatly to preserve—so much so, that they will repay examination from the powers of the microscope, a feature somewhat remarkable and unusual. The teeth are of several different kinds, some small, others
THE GEOLOGIST. 57
from a half to one inch or more in length; they are of a bright glossy texture, aud some of them curved and striated.
It may, indeed it must be, difficult to describe these fossils ina way at all satisfactory in a notice of this kind, and would seem to merit a fuller description hereafter.* It may, however, be remarked that the first of the scales under notice appears of an elongated form, resembling in shape a small leaf of about an inch in length by one-sixth or one-fourth of an inch wide; its markings are, however, very singular and beautiful. The sketch of it herewith may tend to give some idea of its
shape, but the general features and minute cellular structure are wanting. Iam led tosuppose that this scale must be classed with the Ganoids, although much thinner in its structure than scales of this class generally are. My reason for this conclusion is that it is not serrated at the edges, a distinction which Professor Agassiz makes in reference to fish scales of the Placoids. In fact, I find that nearly all those which are found in my collection assimilate much more to the forms and species of the old red sandstone formation, so far as I have teen able to trace them in his voluminous work.
The more my researches into this subject have extended, the more incapable I appear to myself to do anything like justice in the elucida- tion of the structure of the scales and other remains of these extinct fish. In fact, it would appear to me to require more space and time than I have already given to the subject, fully to detail any one specimen. So convinced do I feel of this fact, that I have almost considered it advisable to begin de novo, or relinquish it altogether; but as my remarks, however desultory, may tend to aid some future adventurer, and may serve as a pioneer or guide to those who reside in the coal districts, I cannot relinquish the attempt; and, having entered on a somewhat new and untrodden path, future discoverers will make ample allowance for the difficulties which at present I may have to contend with.
* A more definite description, accompanied with woodcuts, will be supplemented in a future number. ul
58 THE GEOLOGIST.
If it be true, as Emmerson suggests, that there is nothing in the material world but what has its affinity in the region of mind, or which has its relation to the imaginative part of the rational creation, then may I infer that I was led to a search for these fossils by an intuitive instinet, for certainly there was little outward indication to lead me on. If anything in nature could be hidden, this was an instance of the kind ; for when exposed to the gaze of some around me, the truth of the discovery was even then doubted, and it was only by a constant reference to them, and further investigation, that I could assure my friends of the importance due to it: but subsequent and more important objects attained, did not fail to convince the more incredulous.
The carboniferous matter in which these fossils are found has tended very much to preserve them in their entirety: the impressions are, in fact, the fossils; the scales themselves appear to possess much of their original composition, so do the bones—they are bones and scales still, and not petrifactions; and if I were asked to account for this, I should attribute it to that remarkable property which carbonaceous matter seems to have ; for instance, we read of the bodies of men having been found in peat bogs and morasses many years after life had become extinct, not having undergone putrefaction.
The teeth seem to claim more attention than I have been able to give in this imperfect detail; but there is one of so remarkable a character as to merit further notice. I allude to the one before me ; its appearance and shape somewhat resemble the human hand when closed ; the jaw may represent the back of the hand; the teeth, the knuckles and fingers—in fact, it is more of a jaw than teeth; but the teeth and jaw are as much one and the same as the hand and fingers; a tooth will bear extraction in general, but in this instance they are inseparable, as much so as the hand and fingers.
The formation of the scales in these fishes seems to originate from a central axis developing afterwards into numerous cells, which appears to be the case in all animal and vegetable structure. Some of them, as in the macrocephalus, lock into each other at the edges; others again not only appear to radiate from a centre, but have also a ligament in the part from which the scale takes its rise, and is very observable in nearly all of the fossils of the holoptychius, and others for which we have at present no name.
It may be remarked by some that ‘the scales certainly are very
THE GEOLOGIST. 59
interesting objects, as also other portions of the fish; but we should like to see some representation of the complete fish.” We reply, that no perfect specimen has yet been found, or any near approximation to a perfect fish or reptile, in this locality; but we know this, that comparative anatomy is now so far advanced that, with the jaws and teeth, a true representation may be obtained. These we have, and it ouly rests with the comparative anatomist to decipher the whole. It is no slight gain in these discoveries to furnish the requisites for a more complete elucidation.
In conclusion, we see that in the course of time another race of beings is found to occupy the site of one that is past; and who ean tell but that the railroads of this kingdom, which have proved the means of disinterring these and other organic remains, may be one day again submerged, and that fishes may once more luxuriate over the now verdant plains of England? It may be supposed that the race of man will never become extinct so long as the world exists, but we know not
“Thro’ what new scenes and changes we must pass : The wide unbounded prospect lies before us ;”
the future we cannot trace. We do not infer that any new race of creatures will at some future time expatiate on the remains which man may have left on record of his existence on the face of this globe. The importance of mind, with its endowments, bespeaks a change from an earthly character to one more spiritual and refined, so that in all pro- bability we are fast hastening to the last stage of the drama; and that what has been earthly and sensual will become ethereal and spiritual. The physiological condition of this planet indicates that man, like the inferior creatures around him, has passed the subordinate stages of animal existence, clothed with beauty as many of those scenes undoubtedly were in the history of the past; still, the present like to it, is only an inferior condition of his being, the embryo of his existence, the threshold of the future. He looks upon the past as one scene of imperfect organism with all its wonderful development, and this wonder enhances his curiosity to know what is still awaiting him; he finds himself tied to earth and its laws, as it regards his corporeal existence, but he longs to soar beyond the present, and attain to that future good which the Creator has dimly shadowed forth in the pages of Revelation. H 2
60 THE GEOLOGIST.
THE COMMON FOSSILS OF THE BRITISH ROCKS. By S. J. Maciz, Esa., F.G.S., F.S.A., &., &e.
CHAPTER I. The nature of Fossils and their value. (Continued from page 29.)
More things remain to be spoken of fossils; wonders of skill to be pre- sented in their construction and design; marvels of mechanical devices for progression, for strength, for lightness, or for protection to be dis- played; and consummate wisdom and benevolent forethought to be exhibited in their adaptation to the various purposes for which they were created—in fact, asmuch as we find to admire or to consider in the structure of existing animals or plants, in their means of developement or of growth, in the influences of climate and seasons upon them, so much also do we find for equal admiration and reflection in those
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ancient ‘‘ medals” of past creations.
Eyen contorted and damaged fossils are not without their evidences.
Lign 9.—Ammonites varians, from the chalk marl of Dover, distorted by pressure. Squeezed on either side or flattened, they do not merely ndicate the pressure to which they have been subjected, but the direction also from which it came. Everything connected with fossils is of high interest ; but from first to last the value of fossils is in their teachings; and i is never by pounds, shillings, and pence that we can value them at all. In such alight they are but worthless bits of stone, as fit to mend the roads as to be saved. To minds that esteem them thus, they are no treasures, but merely merchandise. Properly studied, however, they con- vey their lessons of the past; and when regarded as letters in the vast and
THE GEOLOGIST. 61
holy book of Nature, which must ever be read with solemnity and reve- rence, they take their places properly in the great sentences and wonderful passages of that mysterious language from which Geology interprets the order, wisdom, goodness, and prescience displayed in the animated worlds that were. It is thus we shall have attained to the true know- ledge of the value of fossils, when we shall turn from such readings with adoration to the Great Author of all.
CHAPTER II.
The Rocks—their order and their teachings. “Pour off thy shoes from thy feet, for the ground on which thou standest
>
is holy.” And the ground on which we stand 7s holy. Holy in its venerable age, and with the impress of Divinity; and when with solemn reverence we approach the consideration of its eventful history, and the skilfulness of its design, are we less in the presence of God than was the Lawgiver of old standing, with another purpose, before the burning bush? There is a time for all things—to be gay and to be solemn ; and there will be occasions for a lighter style than we think fit in this place to pen our thoughts. We design not to treat of the value of the rocks nor of their uses, but to draw from them some of those heart-felt lessons which rank amongst the highest efforts and best results of the grand science of the earth.
We begin with the order of the rocks. Is there skill in the con- struction and organization of our bodies, is there marvellous mystery in the wonderful connection of our corporeal parts with our souls, in the combination of the material with the immaterial, of bodily existence with spiritual existence, of the animate with the in- animate, of senseless matter with the sense-pervaded, sense-pervading, ethereal, and immortal spirit? Is there less of the mysterious and wonderful in the minute but living monad—anything less incom- prehensible in the living but mind-deficient plant and tree? Is there not skill and perfection, design, and a sustaining hand visible in all around us? And is the great globe orderless and chaotic? No! The hand that fashioned and created, the great mind that planned and endowed with specialities the living creature of a day or of three-score
62 THE GEOLOGIST.
years and ten, has laboured for inconceivable millions of years in the fashioning and perfecting of our world —even the senseless winds and waters seem to have joined in effort with the other more subtle powers in the general progress and elaboration of its structure.
Deep down below, covered by a thousand feet of stone—so modern borings have taught us—are the ancient mountain ridges of the primitive world. Deep down below, in their mysterious plutonism, are the erystalline primordial granites, and stacked above them are the ponder- ous stony records of the past creations and ages. Deep down below, and far back into time, must the mind by perception penetrate when it begins to study the order of the rocks; and, without ineulcating some- thing of the knowledge of the regularity of their succession, and the catastrophes by which that succession has been variously interrupted at particular times and places, how could we hope, when we opened and read from the great historical folios of those creations, which for ever have passed away, that our words would be intelligible or understood ?
Much as is known of the rocks themselves, much yet remains to be discovered : there are wide fields yet to be trodden, wide gaps in our investigations yet to be filled up. Theories and systems are after all but the exposition of the existing knowledge of the time, and the prevalent ideas of one age have been deemed to be folly and ignorance in another. Men’s inferences may have changed, but the facts remain; and every year is bringing us nearer and nearer to the truth, however far we may be, notwithstanding all our advance, from a full knowledge of all the laws of nature. Those laws have ever been the same, before even the great foundation-stone was laid on which the superstructure of the fossiliferous rocks has since been raised.
All soils or earths—rocks, as they are technically called—are divided into two classes or groups; the one stratified or in layers (strata) and mechanically deposited by water from the degradation or waste of pre- existing mineral substances ; the other igneous, that is fire-formed or fire-altered, such as volcanic lavas and granite. An intermediate class, the metamorphic, is produced where the former or aqueous beds have been brought into contact with the latter—the heat of the one having changed the characters of the other—in the vicinity of, and often to some considerable distance from, the point of junction. The heat has also destroyed or obliterated, to a greater or less degree, the traces of organized fossils.
a” a a a a eee
THE GEOLOGIST. 63
T have here to request that, for the present at least, it may be taken for granted that the beds or strata are presented in regular series or succession, containing the remains of ancient animals and plants, which have been of very different characters, at those different periods, or systems, into which the past history of our own planet is divided.
Probably many of my readers will have acquired much of this elementary information from the numerous popular treatises which have been produced by so many of our eminent geologists, although there are still many to whom even these primary tenets of our science will be new. For their sakes, therefore, I repeat that which I know to be familiar to others.
Even those who know the general features of the science will not suffer by a repetition occasionally of the knowledge they have acquired, and as never an artist who sits down to draw an oft-repeated scene pro- duces a fac-simile of his predecessors’ works, so the geologist, though he repeats an old tale, still embodies something of his feelings and of himself in the new picture which he paints. The accompanying tables will display the principal divisional arrangements of the various earths or rocks, and will aid tho uninitiated reader in following our remarks.
DNSTRATIFIED ROCKS,
Plutonic. Voleanie. Rocks subjected to heat | Rocks the produce of neath the surface and not ancient volcanos; often
ejected like lava, although Example: |ejected as in modern often protruded in rugged { Granite. eruptions.
masses through the disrupt- Examples—Basalt, Trap, ed beds of stratified rocks. ) Lava,
STRATIFIED ROCKS.
Rocks formed by the deposition from water of the sediments derived from pre-existing materials. These are grouped into great divisions called systems, representing periods in time, the rocks thus associated together having a collactive relationship. The members of each group, while presenting also some general linking features among themselves, are nevertheless marked by distinctive characters which more or less separate them from each other.
64 THE GEOLOGIST.
THE ORDER OF THE ROCKS.
GROUPS. AZOIC—A (Gr.) without; Zoe, Oldest sedi- life: from the presumed ab- mentary rocks. sence of organic remains. Harleck grits, Longmynd flags
and schists, First Period. PRIMARY
of authors.
(The old authors included Granite, Slates, and the multifarious rocks called ‘ Grauwacke,” under the term Primary.) Lower Silurian or Cambrian.
PALOZOIC—Palaios (Gr.) od; | Upper Silurian.
. Devonian. Zoe, life.
Carboniferous.
a a a a ON
Permian.
Triassic.
Second Period. Liassic.
SECONDARY pee aa (Gr.) maddie ; Oolitie or Juras- of authors. life. sic. Wealden. Cretaceous. so Third Period. | Miccoas! TERTIARY CAENOZOIC—Kainos (Gr.), new ;
Lower Pliocene
of authors. Zoe, life. Pleistocene or Upper Pliocene. Gaudaloupe Fourth Period. limestone. RECENT. Includes all rocks, volcanic or |Modern shell- In part Quarter- sedimentary, formed since the { _ sandstone. nary of some creation of man. Travertin. authors. Tufa, &e. Vegetable Soils.
(To be continued.)
THE GEOLOGIST. 65
FOREIGN CORRESPONDENCE.
By Dr. T. L. Pareson, or Parts.
The Emerald and its green colour—Its analysis and formation— Green Gypsum in the Emerald mines—More artificial minerals—Hyalite, Wollastonite, and Aphophyllite—Quartz, Feldspar, and Pyroxen— Feldspar in the lava of volcanos — Petrifaction and Epigenesis — Spontaneous crystallisation of amorphous bodies—Hardening of rocks by exposure to the wir— Extraordinary origin attributed to oolite rocks— Modern oolite discovered by Leopold Von Buch—More Footprinés in the Jurassic formations.
One of the most interesting results has just been obtained by a thorough chemical investigation of the emerald. ‘This interesting mineral, which has given rise to so much discussion as to its composition, its formation, its colouring matter, &c., may now be looked upon with still greater interest since the researches of M. Lewy have been made known. The ingenious chemist just named, in a visit to the mine called Muso, in New Grenada, Mexico, was lucky enough to procure some very fine specimens of emeralds, and of the rock in which these precious stones are found. The first thing that struck him, on receiving these specimens from the hands of the miners, was the excessive fragility of the stones: the largest and finest emeralds could be actually reduced to powder by a slight squeezing or rubbing between the fingers.
It is a well-known fact that the ancient inhabitants of this part of America used to judge the value of the emerald by its hardness. So little had they observed the phenomenon of which we speak, that their principal test consisted in striking a hard blow upon the stones as soon as they were extracted from the earth : if they resisted they were considered perfect stones, if not they were thrown aside as valueless articles. M. Bousingault remarks that in this manner, no doubt, a great number of very valuable specimens have, in former times, been destroyed.
A certain space of time and repose are required for these soft emeralds to assume the hardness which renders them valuable as precious stones. The fine specimens destined for the lapidary and the jeweller must be
66 THE GEOLOGIST.
stowed away with the greatest care for a few days. As to the cause of this hardening of stones recently extracted from their natural beds we shall have occasion of referring to it presently.
M. Lewy has shown also in his interesting paper (Researches on the Formation and Composition of Emeralds),* that the beautiful green colour, so much admired in the stones of which we are speaking, and without which they would, in all probability, be valueless, is owed to an organic substance somewhat similar to that called chlorophylle, which colours the leaves of plants.| The green colour of emeralds has always been attributed to a slight quantity of chromic oxide, which, although it certainly does play an important part in the coloration of other minerals, has positively nothing to do with that of emeralds. Analysis has furnished only an exceedingly slight quantity of chromic oxide ; so small, indeed, that the distinguished chemist whose work we are analysing could not weigh it separately. Our readers have, perhaps, heard of, or seen, a mineral called ouwarovite, a sort of chromiferous garnet, whose green colour (which withstands heat, whilst that of the emerald does not) is exactly that of the emerald; but ouwarovite furnishes 23 and-a-half per cent. of oxide of chrome, whereas in emeralds, as we have seen, there is only a slight vestige of this green oxide. This is certainly a new and unexpected result.
A certain number of facts related in his memoir lead M. Lewy to affirm that emeralds have been deposited from water. It would, perhaps | be more rational to say that water has been active in their production { —First, besides the organic colouring matter, emeralds contain about 2 per cent. of water. In the next place, the black white-veined lime- stone in which they are found contains fossil ammonites. This lime- stone, perfectly freed from the microscopic emeralds with which it is strewed, by digestion with dilute hydrochloric acid, gives in analysis a
roivoth part of glucina.
Great. uncertainty has prevailed as to the mineral constituents of the emerald and its true chemical formula; this has determined me to give here the numbers obtained by M. Lewy, and to corroborate them by
* Presented to the Academy of Sciences, Nov. 15th, 1857.
+ It is, perhaps, as well to observe that M. Lewy has not ascertained if this organic substance in the emerald contains oxygen or not. He seems to consider it as a carburet of hydrogen.
{ See further, the phenomena recently observed by M. Daubrée.
THE GEOLOGIST. 67
showing, at the same time, the results obtained, some years ago, by M. Moberg, in the analysis of some emeralds from Finland :—
Emeralds from Mexico (M. Lewy). Emeralds from Finland (M. Moberg).
RiLiGHIATh uF) Pat | OueOurem tele ireen oe getasiy ea LOundoG
INO hs Ls Oieceia oy bes aeration, a BLO 200
LE CITCTED economy yee lo Sal ell Aimee aie ilen 1741 ( 17(
Bigenesia xh 0:9) fi Pere) eed as
Oxide of iron ee Avie ds th sade t5 Be ae
Cail Son Aes CUS h Se Opacity Omen ae
Titanic acid . traces 0:28
Both these analyses show that the emerald contains 1 atom of alumina, 1 atom of glucina, and four atoms of silica. In that of M. Lewy
slight traces of chromic oxide were weighed with the magnesia, and probably some titanic acid with the alumina. The green colour of the emerald is darker in those specimens which furnish to analysis most organic matter; it is completely destroyed by heat, the stone becoming white and opaque.
On the communication of these results to the Academy, M. Bousingault observed that he also, in former days, had visited the Muso mine, and that he had picked out of the strata in which the emeralds are found, pieces of gypsum of a beautiful green colour, resembling that of the emerald. He had no doubt, from M. Lewy’s observations, that the green colouring with which the gypsum was impregnated was identical with that just discovered by M. Lewy in emeralds.
M. Daubrée has furnished us with some new and interesting details concerning the artificial production of minerals. By a close observation of the methods employed by nature, and a certain intrepidity in the laboratory, this enthusiastic geologist has had the good fortune to produce some crystallized specimens of minerals which have never before been purposely formed or accidentally found in scorie. He formerly observed in the mineral springs at Plombiéres, the waters of which contain silicate of potash and soda, and have a temperature of + 70° Centigrade, the formation of certain well-known silicates and other minerals usually found in the veins of eruptive or primitive rocks. Most of these have been formed, since the time of the Romans, in the orifices of the mineral springs in question. An old Roman tap in bronze was found covered with a crust of sulphide of copper which,
68 THE GEOLOGIST.
from its aspect, its crystalline form,* and its other properties, it was impossible to distinguish from the Cornwall specimens.
The masonry near the springs was often seen to be impregnated with hyalite (a sort of transparent silica) in every respect similar to the hyalite found in basalt rocks; and sometimes apophyllite (silicate of potash and lime) showed itself in very neat crystals. We would observe here Wochler succeeded formerly in dissolving and erystallizing this mineral by the aid of water at 180° Centigrade.
M. Daubrée asked himself this question : [f we find hydrated silicates formed slowly in mineral springs at no very high temperature, is it not probable that anhydrous silicates may be artificially and more quickly produced by the action of water at a higher temperature? Numerous experiments have answered this question in a most affirmative manner. They consisted principally in submitting the different substances in presence of water, to a heat of 400° Centigrade for a month together, in a closed glass tube, enveloped and protected by an iron case.
As glass formed part of the apparatus, it naturally occurred to him to determine first of all, what would be the result of this treatment on glass itself. It was soon found that this substance undergoes, by the simple action of water at this temperature, a complete decomposition : it first becomes opaque, earthy, and fragile, resembling kaolin, then it gradually and regularly swells and transforms itself into a host of minute crystals, which were found on examination to be wollastonite (3 Ca 0, Si 0°); at the same time the alcalis of the glass, and a certain quantity of silica, are dissolved. Soon, however, silica is deposited in the form of crystallised quartz, of which some of the crystals measure two millimeters in length. The presence of alumina modifies these phenomena; thus, when obsidian was acted upon in like manner, minute crystals of feldspar were obtained, resembling, en masse, granular trachyte. Clay and kaolin, which had been previously purified by washing, on being sub- mitted to a similar treatment, gave birth to feldspar, mixed with crystals of quartz; and if the glass, in the first experiment, is decom- posed in presence of oxide of iron, not wollastonite, but pyroxen, is obtained—the samples of which immediately remind us of the natural erystals found in the Tyrol, Piedmont, at the Somma, &e. They are
* The natural specimens of sulphide of copper are dimorphous with the sulphide of the laboratory.
THE GEOLOGIST. 69
beautifully crystallised, and possess both their green colour and their usual transparency.
From these investigations, M. Daubrée feels justified in concluding that a great number of silicates—perhaps all—found in the primitive crystalline rocks, have been formed by the influence of water at a high temperature; which temperature is, however, very inferior to that of the point of fusion of these silicates. He seems to think that the granite rocks themselves very probably owe their formation and crystalline appearance to similar causes. We must content ourselves here by indicating the result of experiment, and be silent as regards discussion. If the experiments just related, and which are being continued by M. Daubrée, are repeated with success, his conclusions will appear certainly very natural. The most striking feature in his paper is, without doubt, the formation, in the above circumstances, of feldspar—a rock so universally spread throughout nature, and which plays so important a part as constituent of almost all the primary or eruptive rocks. Although crystals of feldspar have been discovered in scoriz, and, by Heine, in the refuse of a furnace for copper fusing,* it appears from Humboldt’s statement + that they have never before been purposely formed :—‘‘ Nor have chemists,” says he, ‘‘ever succeeded in artificially producing either feldspar or horneblend.” It may be well to add that feldspar is daily formed under our eyes in the lava of volcanos. Since M. Daubrée’s observations have come to light, this must doubtless be attributed to the abundant quantity of water incor- porated in lava until it becomes completely solidified.
M. Kuhlmann, of Lille, has published a long memoir on siliceous infiltration or petrifaction, and on epigenesis. { In this work the learned author, who has already done so much for the advancement of chemical and geological science, has presented us with nothing very new. He explains the curious phenomenon of petrifaction by the action of carbonic acid, or of carbonate of ammonia, on the silicates of potash and soda invariably found in spring water. A similar theory has been already professed and published by others, and, I believe, by M. Kuhlmann himself.
The phenomenon of petrifaction is certainly one of the most curious processes in nature. Is it not wonderful to find the soft stem of
* They were analysed by Kersten. T Cosmos, Vol. I. { Comptes Rendus, Nov. 9, 1857.
70 THE GEOLOGIST.
some well-known plant transformed into a hard stone, and yet retaining most of its colour and external appearance? Let us see how this happens. In one of the paragraphs of our last article we had occasion to notice the action of water upon the so-called Plutonic rocks. We have seen that an alcaline silicate is invariably dissolved out of the rock by water. In nature this silicate is carried away by the rain- water to fertilize the earth; it is absorbed with the water by plants, many of which rob it of its silica in an extraordinary manner. Vege- tables are known to evolve in the act of respiration, and more especially at night, a certain quantity of carbonic acid. We know also that this acid decomposes silicate of potash or soda, and in a few hours precipitates the silica of these salts. It is in this way that the different grasses and the plants of the genus Equisetum, &c., retain in ‘their tissues considerable quantities of silica, especially in the green parts of the epidermis or cuticle, where the function of respiration is most active.* But when a piece of wood undergoes decomposition, and becomes brown and decayed, it also evolves a great quantity of carbonic acid, which acts on the alcaline silicates with which the wood is often imbued by the absorption of spring water, in the way we have just described, and precipitates their silica. In this manner, for every atom of carbonic acid furnished by the carbon of the decaying vege- table, an atom of silica is substituted; so that, after a certain space of time, the entire tissue of the plant is converted into a tissue of hard stone. | Animal substances, such as the bodies of polypes, mollusca, &e., furnish principally carbonate of ammonia by decomposition. This volatile salt acts upon the silicates of potash and soda in the same way as carbonic acid, explaining to us at once the manner in which the petrifaction of shell-fish and other animals takes place.
But to return to M. Kuhlman—the most important part of his memoir relates to epigenie forms (or the covering over or replacing of one mineral species by another, without change of form). He has en-
* It is a well-known fact that certain sugar-canes, bamboos, &c., will often strike fire with steel, on account of the large quantity of silica contained in the bark of their stems.
{ The colouring matter of the bark of the trees being accompanied by tannic acid and other substances which have the faculty of preventing, in a great degree, putrefaction or decomposition, is often most beautifully preserved in petrified specimens of woods,
THE GEOLOGIST. 71
eavoured to demonstrate that whenever, in nature, a chemical decomposition takes place very slowly, the products are crystalline, and assume the forms of the pre-existing body ;* whenever the decomposi- tion takes place abruptly we obtain, on the contrary, amorphous precipitates or bodies devoid of crystalline structure. Amongst other experiments, M. Kuhlmann has shown that a current of sulphuretted hydrogen transforms many salts of lead into sulphide of lead without producing a change in their structure, thus explaining certain anomalous forms observed in nature. A current of ammonia transforms pyrolusite into protoxide of manganese without producing a change in the form of the crystals of the first. Nascent hydrogen has the same effect whilst reducing certain metallic salts, &e.
The same author has, more recently, made a very interesting study of the spontaneous crystallisation of amorphous bodies. It has no doubt happened to many of our readers to pick up pieces of common flint in which certain parts are profusely crystallised, or studded with minute transparent crystals of quartz. It has been M. Kuhlmann’s object to show how these crystals have been formed, and to explain other like phenomena. Numerous observations have shown him that amorphous or earthy matters in general have a great tendency to crystallise by slow desiccation; and he has shown by experiment that, in time, many substances, at first apparently without structure of any sort or kind, will take crystallised forms. ‘This is perfectly illustrated by malate of lead, which, as every chemist knows, is produced in the form of an amorphous precipitate, but which after being allowed to repose for a certain time, shoots out into crystals. M. Kuhlmann has shown that in any substance the crystals produced in this manner are neater, or better defined when the drying has proceeded very slowly.| The siliceous deposits formed at the present time by the geysers of Iceland furnish numerous examples of the spontaneous crystallisation of which we speak.
It has been frequently observed that when a piece of rock, or a
* Thus we see sulphate of potash placed in damp chalk, transform itself slowly into gypsum without losing its crystalline form (according to Beudant).
+ The same holds true, to a certain extent, for volcanic lava, both ancient and modern, which furnish very different products, according as their cooling has been rapid or slow. In the first case they often form a black non-crystalline glass ; in the latter, a stony mass of crystalline structure.
72 THE GEOLOGIST.
mineral, is freshly taken from the quarry, it is often much softer or more fragile than when it has remained some timeexposed to the air, as we have already remarked with regard to the emerald. This is very munifest, for instance, in newly-made marble slabs, which, if they are placed against a wall in an inclined position, are apt to bend, and become in a great measure valueless to the owners. After a few days’ exposure to the air the rock or mineral becomes hard, losing at the same time a considerable quantity of water. M. Kuhlmann has endeavoured to prove that this hardening of the rock and expulsion of water are not owed to simple evaporation or drying, but to a process of crystallisation which takes place slowly from the moment the rock is exposed to the air.
Natural crystals are often found strewed on a rock of their own com- position, which rock, in M. Kuhlmann’s idea, has given birth to the erystals in question by a species of contraction or slow crystallisation, accompanied by loss of water—phenomena which he has artificially produced with sulphate of baryta, sulphuret of mercury, oxyde of copper, &c. He explains in like manner the origin of the beautiful crystals found in geodes.
M. Virlet D’Aoust, civil engineer, has lately presented to the Academy of Sciences a paper on the eggs of certain aquatic insects found in Mexico, and which he looks upon as the means by which oolitic rocks have been, and are still being, formed. However extra- ordinary—we might, perhaps, say mysterious—this origin of oolites may appear, we must not be too hasty in rejecting the statements brought forward by the author, whom we believe to be a man of some geological experience, and a clever engineer. Has not Ehrenberg shown that immense masses of the earth’s surface owe their origin to a profusion of microscopic infusoria, foraminifere, &c.? M. Virlet D’Aoust, in his turn, endeavours to show that oolitic rocks owe their existence to myriads of minute eggs, the seed of some aquatic insects. Here are the facts observed :—
Everyone has heard of the great plain of Mexico, situated some 2,300 meters above the level of the sea. Near the centre of this tract of land are seen two large lakes.* The first, the water of which is
* It was from these large Mexican lakes that Humboldt brought back with him
Scheuzher’s antidiluian man (homo diluvii testis), a large salamander belonging to the most recent freshwater formations.
THE GEOLOGIST. 73
fresh, goes by the name of Chalco, the second is a saltwater lake called Texcoco. The observations made by M. Virlet led him to discover that the bottoms of both these lakes are formed by a sort of grey limestone of modern formation, containing small oolites which, in the author’s eyes, are in every respect similar to those found in the rocks of the Jura formation. He immediately made known this fact to Mr. Bowring, director of the salt works at Texcoco, who informed him that these oolites were owed simply to the incrustation of the eggs of water insects by the carbonate of lime daily deposited from the waters of the lakes. In a second excursion to the lakes the author remarked that their banks were strewed, under water, with an infinite number of insects eggs, about the size of a pin’s head, and which appeared to be those of a new species of boat-fly (Notoneeta). The Mexicans consume immense quantities of these eggs at their meals. They are extracted from the water by means of bundles of reeds or grass, on which the insects deposit their eggs by millions ata time. M. Virlet is not only convinced that these modern oolites of Mexico owe their origin to the eggs of a species of boat-fly, but seems to think also that the oolite of the Jura, and other ancient strata, must be attributed to a similar cause. ‘‘ This explains,” says he, “ the irregular distribution of oolitic grains in the rocks of the Jurassic strata. Where the oolite is hollow, the egg has been enclosed before being’ hatched; where the oolitic globules are completely solid, the eggs have had time to hatch, and the cavities left by the exit of the larve have been filled up by the in- crusting limestone.
If these facts are confirmed by future observation, it will not be without interest that we shall recall the Greek origin of the word oolite (Qov, egg; Aulos, stone). I would, however, on this occasion remind our readers that.a small oolitic bed, bearing great resemblance to the Jura limestone, was formerly discovered by Leopold von Buch * near Teguiza in Lancerote—one of the Canary Islands. This oolite bed is also of modern formation, and probably continues increasing at the present time. It would, therefore, be of great geological interest to ascertain if the oolitie deposit made known to us by Leopold von Buch owes its origin to causes similar to those stated by M. Virlet in reference to the Mexican oolite. Such an investigation, which could
* Canarishe inseln.
74 THE GEOLOGIST.
be easily made by the English vessels which frequently visit the Canary Islands, would be more likely to decide the important question than the examination of: ancient oolites with a view to discover some organic remains that might be attributed to the eggs of insects.
In my last article I mentioned a curious discovery of footprints made by M. Daubrée in the Jurassic formations at St. Valberg. Since then, the celebrated naturalist, M. Paul Gervais, has brought forward some interesting facts of a similar kind. In a short paper addressed to the Academy of Sciences, he describes some footprints of extinct animals found in strata corresponding to those observed by M. Daubrée. The impressions he speaks of have been recently discovered by himself and some friends at Foziére, near Lodéve, in the south of Franee. They were observed on the surface of slabs of sandstone alternating with beds of marl, and are exactly similar to the footmarks found some years ago at Hildbourghausen in Saxony, at St. Valberg in France, and, as M. Paul Gervais remarks, resembling those formerly discovered at Storton-Hill, near Liverpool. The learned author observes, that until further evidence can be furnished as to whether these footprints belong to mammalia or reptiles, he will maintain the opinion of those naturalists who consider them as being owed to large amphibious animals, whose bones and teeth abound in certain parts of the Trias beds. These am- phibious reptiles are those which Owen, de Munster, Jaegar, Fitzinger, Hermann Meyer, and other naturalists have described as large Salaman- ders, Mastodonosauri, Batrachosauri, Labyrinthodonts, &e. Paul Gervais himself, and Hermann Meyer, first made known the remains of these animals in France, in the variegated sandstone near Soultz-les-Bains, (Bas-Rhin), and in the Muschelkalk at Tunéville, and Fleming (Meurthe).
The characters of the footprints observed by Paul Gervais, near Lodéve, answer to the form of animal described by Kaup as Chirotherium, or Chirosaurus Barthii. The details given by the author as to the con- figuration, the strata, and circumstances in which they were found, &c., are precisely identical to those related by M. Daubrée (see our last paper). Like the latter, M. Paul Gervais has observed by the side of the larger marks, others, belonging evidently to some smaller animal, and showing four digital impressions; the author thinks these must be attributed to a species of palmipede. A third species of footprints was likewise observed, consisting of a star-like impression formed by four
THE GHOLOGIST. 75
toes of unequal length, and attributed to an extinct bird known to American naturalists by the name of ornitichnites.
An interesting collection of these footprints has been deposited by the order of M. Paul Gervais in the Geological Gallery of the Faculty of Sciences at Montpellier, where they may be examined at leisure by naturalists visiting that town.
BETTER FROM THE BEY 5.4 KINGS LYY., RECTOR OF EVERSLEY. (To the Editor of the Gxroxoatst.)
Dear Srx,—I have read with great pleasure and also great hope, your first number—and am especially delighted to find that you aim at spreading a popular knowledge of Geology. May I, in further- ance of this object, make a suggestion? Why not establish in your magazine a regular geological ‘‘ Notes and Queries ”’ department ?
There are hundreds, if not thousands, who have no time to work out geological problems for themselves; who yet are most desirous of in- struction, and would receive the results of the science frankly and trust- fully. Artizans desirous of self-instruction, and ladies of rank desirous of instructing their children would, alike, be glad to know a hundred things which, not having books, time, or perhaps scientific habits of mind, they cannot find out for themselves. If a knot of wise men, and such a clergyman as Mr. Brodie among them, would deign to explain to these people their puzzles, they would be doing a noble work, and sowing good seed in many minds which would bear fruit ina future generation, by freeing it from childhood, from the bonds of many superstitions and traditions of altogether human invention.
May I give an instance in which I myself appear in the character of one begging for information ?
Last summer, in the Isle of Purbeck, I was told of a wonderful rock, the Haggerstone,* which lay on the top of a Qjll in the northern moors of the Isle, overlooking Poole Harbour. ‘‘ Would I go and see it?” For nobody agreed how it got here. ‘It was a proof of Noah’s
* Query.—Hag’s Stone ; Hexe’s Stone; Witches’ Stone. 12
76 THE GEOLOGIST.
Deluge.” ‘It had been washed up to its present elevation by a flood.” ‘‘It had been formed” (this I think was the suggestion of © a Reverend Brother) “by sands blown up the hill from the mouth of Poole Harbour”!!! and so forth—some of the theories being not much in advance of that of the country folk, ‘that the devil had dropped it there” (as he is in the habit of dropping boulders in many counties) ‘‘ during a nightly excursion for the purpose of blocking up Poole Harbour mouth.’”’ I went, and found a noble rock indeed—a cube of some twenty feet—on an isolated heather peak looking far and wide over moor and sea, with an old black-cock washing his steel-blue jacket in the sand at its foot.
A glance showed me that it was no boulder, but a remnant of partially- removed tertiary strata, probably still a situ, though it might have sunk to a lower level from the abrasion of softer beds beneath.
But (and here my ignorance cries for help) I found that its innumerable strata, and the gravel around, were not composed of the same materials as the Bagshot and New Forest beds, with which I am tolerably acquainted, but of coarse quartz grit, mixed with a dark grit, apparently fragments of trap.
Now will any kind and wise man tell me (1) How they got there ? (2) Whether they came from the Dartmoor granites and South Devon traps? (3) Whether they have any connexion with the vast beds of porcelain clay which are spread over the basin of Poole Harbour, a few miles off? One could not help faneying that the soluble silicates of alumina from the disintegrated metamorphic rocks lay below in the deeper basin, while the coarser grit had been washed on to the shores of the estuary to be upheaved afterwards on the shoulders of the Corfe chalk ridge: but guesses are useless without investigation; and I was leaving the place ina day or two, and did not know but that the whole subject had been worked out already by some wiser man. Am I, therefore, to be debarred from learning at second hand what I had no means of discovering at first hand? And how can I more easily learn than through such a ‘ Notes and Queries ”’ department as I recommend to you? im
Conceive hundreds of people having each a question like mine to ask, and a dozen kind-hearted sages who will bear with our ignorance (often I fear with our silliness) and answer, at least, ‘‘ If you will read such and such a book, you will find out all about it.” And you will see
THE GEOLOGIST. 77
that there is plenty of scattered good (for all teaching is good) to be done ; and also plenty of possible subscribers to your magazine, when it has taken a shape which will bear on them. Believe me, Your thorough well-wisher, C. KINGSLEY, F.L.S., F.S.A., &e.
[In one ofthe prospectuses in which Tur Gronocist was an- nounced, it was describel as “a general gazette of Geology,” “a geological ‘Netes and Queries;’” and it was with the view of establishing a ‘‘ Notes and Queries” department, or something equiva- lent thereto, that students and others who might wish for information were invited to send their questions to the editor of this magazine. We beg leave to call particular attention to this invitation, which will be found repeated this month on the second page of the cover. It is gratifying to find our plan approved by a man so well qualified to give an opinion on the subject as Mr. Kingsley; and we hail his letter and the recommendation it contains with great pleasure. We hope that some one or other of our readers, who may have studied the Geology of the Isle of Purbeck, will have the goodness to reply to the questions propounded by our correspondent. The latter will perceive that Wwe now commence a ‘Notes and Queries”? department which will, we hope, eventually attain much larger dimensions, and will serve effectually the purposes for which it is intended.—Ep. or Geotogisr. |
PROCEEDINGS OF THE WARWICKSHIRE NATURALISTY’ AND ARCH ALOGISTS’ FIELD CLUB DURING THE PAST SUMMER.
AxrHoucH this Society has only been established since July, 1854, the number of members now amounts to nearly one hundred, and the meetings have been most agreeable and successful. We think it may interest our readers if we give, from time to time, a short account of the proceedings of the club; and in order to bring it up to the present year, we shall briefly review the labours of the session concluded in October.
The first meeting was held at Chipping Campden, in Gloucestershire, on Tuesday, the 20th of May. A party of fifteen started from Warwick at 8.30, reaching their destination at 11. Here they were joined by only three members of the Cotswold Naturalist’s Club, whom the Warwickshire Club hoped to have met in full force, especially in their own county, but unforeseen causes prevented the attendance of the most active labourers in the field, with the exception of
78 THE GEOLOGIST.
their esteemed Hon. Sec., Professor Buckman, ‘The number was increased by the timely arrival of several Warwickshire naturalists, who all proceeded at once to the church, an ancient structure containing many points of interest, but spoilt, as too many country churches are, by galleries and other deformities. After inspecting this, the archzeologists proceeded to look over the town and neighbour- hood, which occupied them satisfactorily during the afternoon. ‘The geologists and botanists, who mustered in greater strength than usual, went to the spoil banks on the railway, which are the result of the excavations obtained from the Mickleton Tunnel, and which have been long famous for their rare and beautiful fossils. The strata in which they were discovered belong to the top beds of the lower lias, just below the marlstone which is seen cropping out by the side of the banks, on the line, near Mickleton, and on the rising ground adjacent. In the shale and clay below the marlstone are layers of ironstone rich in ore, so much so, that it might be worked with profit; indeed, a similar bed was formerly worked in the same position in the lias at Robinswood Hill, near Gloucester. Associated with it is a bed of sandstone full of organic remains, chiefly marine shells, lying together in masses, in great variety and abundance. The rarer forms obtained at this locality consist of several new species of starfish, ophinra, crustacea, and some echeriodernus, which were first discovered by Mr. Gavyey, the intelligent engineer of the line, and have since been figured and described by the late Pro- fessor Forbes, in the third Decade of the Geological Survey. In the course of the ramble, Professor Buckman, at the request of the Vice-President of the Warwick- shire Club, gave a brief account of the geology of the district ; and thus ended a very pleasant and instructive day, which was rendered still more agreeable by the beauty of the scenery and many other points of interest in the neighbourhood. One of the botanists present discovered an extremely rare, if not an entirely new, plant, which will probably be shortly figured and described.
The second summer meeting was held at Dudley, on the 22nd of June. The members assembled at the Hotel at 10, where they were joined by the Worcester- s hire Naturalist’s Field Club, and, under the guidance of Mr. Fletcher, the party proceeded to the far-famed Wren’s Nest, and the greater part of the day was Spent investigating the many interesting geological features which it presents. It is composed entirely of Wenlock limestone in the upper Silurian series, which here rises up into dome-shaped masses, forming the Castle Hill, Wren’s Nest, aud other lesser elevations, which have been protruded through the surrounding coal formation by igneous action from below. At Rowby and other places these outbursts of igneous rocks are apparent at the surface, and are formed entirely of trap or basalt, which is extensively used as a road-stone. As may be supposed, the strata are highly inclined, and dip away at steep angles on all sides of the anticlinal. On the summit of the hill the Vice-President (Mr. Brodie), at the request of the party, pointed out the geological features of the district, and briefly alluded to the many curious fossils for which it has been long celebrated. Many of the commoner fossils were picked up by the geologists present, who formed a numerous body on this occasion. The view from the hill was said to be extensive, but a combination of mist and smoke obscured every distant object. Returning by the coal-pits, the members were much interested by seeing the upturned beds of the coal formation, which have been raised to the surface by the upheaval of the Wren’s Nest, and dip away from it almost vertically.
The members now reached the Priory and Castle, both of which afford many points of interest to the antiquarian. ‘The morning’s ramble closed with an
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THE GEOLOGIST. 79
inspection of the celebrated Caverns, which were kindly lighted up by the per- mission of Lord Ward, who, unsolicited, offered this act of courtesy to the Clubs. The lighting up of these caves, or rather old deserted quarries, had a most striking effect, and was greeted with loud cheers by the numerous body of spectators. The united Clubs afterwards dined together at the hotel, and a few brief scientific disquisitions—in which Dr. Grindrod, Mr. Brodie, Mr. Lees, &c., took part— terminated a very pleasant and interesting excursion. The united Clubs formed a large party, numbering twenty-seven persons, including Mr. Salter, of the Geological Survey.
The third meeting of the season took place at Coventry, on the 11th of August. The members assembled at the King’s Head Inn at 11.80, and proceeded to the Wyken Colliery, for the purpose of inspecting a portion of the Warwickshire coal-field. Mr. Whittem, the owner of the pits, here explained the character and extent of the coal-bearing strata in the district, which was clearly illustrated by a section of one of the pits. The party being duly equipped in miners’ dresses, went down the shaft with comparative ease and safety, and descended about three hundred feet into the bowels of the earth, under the guidance of Mr. Whittem and the foreman of the pit. Although the examination of the coal in si/u was attended with considerable labour, those present were amply repaid for the instruction afforded them by a personal inspection of a deposit which is one of the most valuable and important in the world. It is very rarely that the coal itself appears at the surface, as most other formations do, and therefore it can only be seen and worked at a considerable depth underground ; and the members of the Fieid Club were glad to avail themselves of this opportunity of seeing the way in which it was obtained, and the position it occupied with reference to tle new red sandstone formation, which it underlies. On their return to the pit’s mouth, there was only sufficient time to examine the quality of the ironstone associated with the coal at another pit, and to bestow a hasty look at a large steam-engine used for forcing up the water from below, which was of excellent quality, and of a slightly mineral character.
The Warwickshire coal-field is of limited extent, tbe principal pits being at Sowe (its south-eastern limit), Wyken, Bedworth, and Nuneaton. It is more or less affected by faults, and a considerable upthrow of trap-rock occurs in one part, where it is extensively quarried, and is similar to that at Hartshill, which is another outburst of the same igneous deposit, and may be traced at intervals as far as Charnwood Forest, in Leicestershire. The quality of the coal is variable, the best being tolerably good. The shale and ironstone associated with it contain the usual carboniferous plants, and, in places, shells belonging to the genera Unio and Mytilus, and an entire and, probably, new species of Limulus, were found at Sowe Colliery some years ago, by the Rey. P. B. Brodie. At Bedworth there isa strong band of fresh-water limestone, containing spircrbis (microconchus) carbonarius, which has also been detected in the Leicestershire, Shropshire, and Lancashire coal-fields. This limestone does not occur at Wyken and Sowe.
A few members who arrived late visited several churches and other places of archeological interest, for which the ancient city of Coventry is famous, and at four o’clock the party, now nearly twenty in number, sat down to dinner. After the usual business of the Society had been transacted, Mr. Whittem, at the request of the President, made a few additional remarks on the coal formation of the district, and Mr. Brodie gave a short account of the discovery of a new and
80 THE GEOLOGIST.
perfect fossil fish in the upper Kenper sandstone, near Warwick. This terminated a very pleasant meeting.
The last meeting of the Club was held on the 15th of September, at Henley in Arden, and was entirely devoted to archology.
The next meeting was fixed to take place as usual at Warwick, in February next, when the chief business of the Club will be transacted, and places of meeting settled for the year ensuing.
NOTES AND QUERIES.
A CoRRESPONDENT writes:—‘‘I beg leave to remark that, within this year (1857), several fossil bones have been discovered in the Lias on the beach between this place ” (Charmouth) ‘and Lyme Regis, which, in my humble opinion, go a great way to overturn the general opinion that the Lias contains no fossil remains of Mammalia. J will, at an early period, endeavour to transmit you asketch of two in my own possession, and two others in that of a gentleman of my acquaintance, who is engaged in pursuits similar to my own. Both of us are zealous collectors— not Geologists, I beg to observe, although we have some specimens which I doubt not would be highly interesting to a professed Geologist.”
Nropuyte.—A silicate is one of those bodies which are called by chemists “salts.” A ‘“salt’’ isa compound which is the result of the union of an “ acid” with a “base.” In the case of a silicate the acid which unites with the base is silicic acid or “‘ silica,’’ the material of flints, rock crystal, &c.; and an alcaline silicate is silica in union with an alkali as the base. ‘The silicates of potash and soda (both alkalies) are soluble in water, and thus rocks containing them may be broken up by the action of water, which dissolves the soluble silicate away, causing the other ingredients to fall to pieces.
X. Y. Z.—Algee are not sponges. They constitute a natural order, consisting of aquatic plants, both marine and freshwater, of which seaweeds are familiar examples. Many of them, especially the freshwater ones, are microscopic objects.—Silt is the fine sediment which is carried down by rivers and deposited on their banks and at their mouths, sometimes in such quantity as to form banks, which block them up, or at least render the navigation intricate and difficult.
Jane E. B.— Ptericthys” means “‘a winged fish,’ and is derived from the Greek words pteron, a wing, and ichthus, a fish.
0. N, Y.—Woodward’s ‘‘ Recent and Fossil Shells,” published by Weale, will answer your purpose.
Verso Sap.—Your suggestion is useful, and has been under consideration, but there are difficulties in the way of carrying it out. A vocabulary for each number of the Magazine would occupy more room than could be afforded for such a purpose. Most elementary works on Geology contain a glossary of terms; we must content ourselves with giving the meaning and etymology of words when asked for them. Fossils are frequently represented im sitw, but those which are found in the bed ‘‘a confused mass of stems, calices, and arms,’’ as the Woodocrini are described to be, cannot, of course, be drawn in this manner.
T. V. writes as follows :—‘ To the Editor of the Geologist.—Sir, If any of your readers will give me the names of the localities in the neighbourhood of Durham, that possess interest for Geological students, it will much oblige.”
THE GEOLOGIST.
MARCH, 1858.
CONTRIBUTIONS TO THE GEOLOGY OF GLOUCESTERSHIRE. By tue Rev. P. B. Broprz, M.A., F.G.S., &c., &e.
(Continued from page 48.)
Havine reviewed, in our first paper on this subject, the upper portion of the Lower Oolite, down to the Stonesfield slate inclusive, we propose in this to give some account of the lowest member of this formation, the Inferior Oolite, and then to pass on, in descending order, to the Lias. The district under consideration has, of late years, been very generally and carefully examined by many able and experienced geologists; but nevertheless additions to our knowledge of its Geology are from time to time being made ; and our own practical experience in the field confirms the belief often expressed by others, that, however much may have been done in any particular spot, there is always something left to reward intelligence and zea
The student, however, must not be discouraged at being at first able to add but few new facts to the list; he must bear in mind that one truth well authenticated is worth a hundred hasty generalizations and un- founded conclusions. The book of Nature is open to all who choose to read it; and he who, studying it in an honest and earnest spirit, adds something to the stock of general knowledge, even though it should be but a little, yet that little is worth recording, and is deserving of support and encouragement from the scientific public. Without actual reference to the wonderful revelations of Geology, our great poet, Shakespeare, has said, almost prophetically, that there are ‘‘sermons in stones, and good in everything ;”’ and, certainly, the geological student may literally adopt this motto. To say nothing of any higher motives, there is a
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secret satisfaction in the discovery of a new fossil, of a flower, or an insect hitherto unknown; and even he, who does nothing more than follow in the track of greater and wiser intellects, is at least a better man than one who is content to pass through life without effecting anything worthy of recording. With these few prefatory remarks of encourage- ment to the beginner diffident of his own powers, or alarmed at the difficulties besetting his path, we must pass on to the more immediate purpose of this article.
The Inferior Oolite is so called from its position below all the other oolitic rocks, and in the order of succession was, therefore, the first formed of the group. It constitutes a very important and prominent feature in the physical geology of Gloucestershire; being thicker there than in any other part of England, and yielding to no other portion of the series in zoological interest. In the vicinity of Cheltenham it forms really a great type section; while the changes and modifications which it undergoes in its extensions on the south and east are only such as might be expected to occur in a cotemporary but distant sea-bottom, of which the stratigraphical conditions would vary with the remoteness of the area, and the organic remains of one portion of which would also be only partially identical with those of other portions.
Leckhampton Hill, near Cheltenham, is one of the best places for examining the strata in detail, and we should recommend the student to commence his investigation at that spot. Ascending by the tramway to the lowest portion of the section exposed on the right hand, the basement beds will be found reposing on the clay of the Upper Lias, although the latter is not always visible, on account of the débris fallen from above. ‘These ‘‘ basement beds” are here much reduced in thickness, but elsewhere they are more largely developed; and we shall therefore reserve what we have to say about them until we describe the localities where they are most advantageously exposed. The stratum immediately above them is termed ‘‘ Pisolite” or pea- grit, and is in many respects a remarkable bed, generally and readily distinguished along the whole line of the outer escarpment of the Cotswolds, from Painswick on the south to Cleeve and Whinchcomb on the north-east. It is usually a hard, coarse, coneretionary rock, made up in a greater or less degree of small flat concretions, which give it a singular aspect, and which might be taken for organized bodies by the uninitiated, as they have sometimes small corals attached. It
BRODLE—GEOLOGY OF GLOUCESTERSHIRE. 83
eontains a great variety of fossils, often well preserved, consisting of marine shells, corals, and echinoderms; the latter are more numerous, both in genera and individuals, in this bed, than in any other por- tion of the Inferior Oolite. Among the testacea are some fine and well-preserved Terebratule, among which Terebratula simplex and Terebratula plicata may be especially enumerated. The surfaces of the blocks are often covered with corals and shells, with fragments of Pentacrinites and claws of crabs, and deserve a careful scrutiny. The pisolite is 38 feet thick at Leckhampton, and 40 feet at Crickley Hill. It should be observed that many organic remains are peculiar to it, and occur nowhere else in the series.
A remarkable change is to be noted in the overlying stratum, the free- stone, both lithologically and zoologically. It isa fine-grained, yellowish oolite, closely resembling that of Bath, a portion of it being good and useful for building. In the upper part there are very few fossils, but the lower portion is almost entirely made up of small shells, in a more or less comminuted state. Nevertheless, by a diligent search, a series of pretty specimens may be obtained at this spot. These broken shells exist also along the western face of the hill towards Crickley. At first sight this stratum appears less rich in specimens than the other divisions of the Inferior Oolite; it has yielded, however, upwards of 160 species of small shelis, the bivalves preponderating in number over the univalves. A few species are limited to the freestone, but others range indis- criminately throughout the group. A considerable number agree speci- fically with forms in the Great Oolite, especially with those of the more shelly beds, in which the marine conditions appear to have been repeated to a certain extent, and which, in other respects, were evidently very similar. This fact is more to be regarded because, as a general rule, the species in the Inferior and Great Oolites are quite distinct, although the genera are for the most part alike. The worn and imperfect condition of the shells shows that the sea in which the freestone was deposited was subject to the movements of frequent and variable currents, which broke up and triturated any organic bodies accumulated therein. In this respect, too, it resembles the Great Oolite. The thickness of the lower freestone is 106 feet. This rock affords a very good example of the oolitic character, the small inorganic oval grains and shelly matter being cemented together by carbonate of lime. The freestone is present in other parts of the Cotswolds ; as at Cleeve, Broadway, and
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Stanway on the east, in the neighbourhood of Stroud and Painswick
on the south, and at Frocesterhill in the same direction, at all of which places it is extensively quarried for economical purposes.
Ascending along the steep path by the tramway toa higher quarry, the full extent of the shelly freestone will be apparent; but here the student will observe that it is divided from a more fragmentary upper band of the same character, to all appearance less fossiliferous, by a cream-coloured marly limestone more or less consolidated, but very dif- ferent in texture and in organic remains from the freestone. Like the Pisolite below, it forms a well-marked line of demarcation, and may be traced from the most eastern Cotswold extension of the Inferior Oolite to its extreme southern limits, where it thins out and disappears. This oolitic marl contains many fossils along the whole line of the Leck- hampton escarpment, especially shells and corals; and, as it is readily acted upon by frost, these may be easily picked out of the matrix. Some of them are distinctive and peculiar, differing from those of any other bed, either in the Great or Inferior Oolite. Univalves are in places abun- dant, and there are many species of Terebratulz, of which Terebratula fimbria, with the test or shell preserved of a silvery whiteness, is the most characteristic. At Leckhampton the corals are less abundant than in some other localities, as at Crickley and Pitchcomb, where from their numbers it may be inferred that they formed part of a small coral-reef beneath the oolitic sea. At Miserden, in the vicinity of Stroud, this stratum is very rich in organic remains, especially univalves, including some long and peculiar Nerinee, and we strongly recommend the collector to visit this spot, as well as Crickley and the quarries at Cleeve, near the ‘Rising Sun” inn. He will at once recognise this band of marl by its position, its fossils, and its chalky appearance wherever it occurs. If he will now climb to the top of the hill and turn to the left, he will reach several quarries, the strata in which indicate considerable lithological and zoological changes, implying oceanic conditions differing widely from those of the inferior subdivisions of this formation. In Sir R. I. Murchison’s ‘‘Geology of Cheltenham,”’ edited by Messrs. Buckman and Strickland, these upper beds are locally termed ‘‘ Trigonia-grit” and ‘‘ Gryphite-grit,” and are underlaid by a brown, rubbly stone, full of well-preserved fossils; above Sandywell Lane the last is charged with a zone of small Tere- bratulea. As these upper grits are by no means constant in their
BRODIE—GEOLOGY OF GLOUCESTERSHIRE. 85
presence or in their distinctive characters southwards, often being inseparable, the term ‘‘ Ragstone”’ is perhaps a better one for the whole set, the thickness of which would amount to 38 feet. The ‘‘Gryphite grit” is a coarse calcareous grit, readily distinguished by the abundance of Gryphea Buckmanni and G. Cymbium, whence its name. Masses of these shells are piled in heaps, and cannot fail to attract the attention of the geologist, who does not, if he is a careful observer, allow any fact, however apparently trifling, to escape him; as it may help him to read the history of the past, and perhaps may prove to be one of the clues to a correct comprehension of some impor- tant fact. Among the numerous fossils associated with these gryphites are occasionally some very large Ammonites, with Ostrea Marshii, Pholadomya, and other fossils, mostly in the form of casts; but at Rodborough Hill, facing Stroud, though much reduced in thickness, the grit is loaded with well-preserved testacea. Palatal teeth of fishes (Acrodus) are occasionally met with there, though scarcely a trace of anything of this kind has been detected in any other of the inferior subdivisions, excepting in the bone-bed at the base of the series at Crickley Hill. Asthe ‘“ Trigonia grit” is not well developed at Leckhampton, and the higher beds are not seen there at all, we must seek them elsewhere, in a southern or north-easterly direction. Thus, at a roadside cutting, called Cold Comfort, five miles south-east of Cheltenham, there is a thin layer of clay and stone dividing the “‘Gryphite grit ” from the “ Trigonia grit,” abounding in univalve and bivalve shells, which are often entire: it is characterized by the large Perna mytiloides.
Near Naunton and Stowe-on-the-Wold, there is a rough white oolitic stone, forming the highest zone of the Inferior Oolite, loaded with specimens of Clypeus Plotii and Nucleolites clunicularis, with Lima gibbosa and other shells. On the Stow road, at Hampden Farm, beyond Andoversford, the ‘ Trigonia grit” is satisfactorily exhibited, and consists of a coarse, ragged limestone almost made up of Trigonia costata, T. clavellata, Terebratula globata, &e. At Rodborough Hill it is about eight feet thick, and in that district occurs as a hard lime- stone, more or less sandy or argillaceous, and almost entirely made up of shells. In this part of the series a very pretty shell, Rhynchonella spinosa, is of frequent occurrence; the test is usually retained, and even the long slender spines may now and then be detected. As this fossil
86 THE GEOLOGIST.
never occurs below the “ ragstone,” it forms a distinguishing mark of the upper zone. In the neighbourhood of Minchinhampton, Mr. Lycett has noticed another and higher stratum, probably the equivalent of the “‘Clypeus grit” of Mr. Hull, which he designates ‘‘ Pholadomya grit.” Mactra gibbosa occurs in it, and numerous specimens of Terebratula globata. If we include the basement-beds, the total thickness of the Inferior Oolite is not less than 280 feet at Leckhampton Hill; of which, nevertheless, it does not form the main part, as there is a much greater thickness of Lias between its outcrop and the level surface of the plain.* This holds good with regard to the outer edge of the Cotswold chain, in its entire range over a considerable area. On the south and east, the Inferior Oolite is much reduced in thickness, and, as we have shown, subject to considerable variations, both in bulk, struc- ture, and fossil contents; some beds being altogether absent or replaced by others; and, if rich in organic remains at one spot, are entirely destitute of them at another. Notwithstanding the depths and con- ditions of the sea frequently varied during the period of its deposit, there is one striking similarity in the beds of this division: viz., the almost entire absence of any terrestrial or fluviatile animals or plants. Marine shells and corals of several genera are the prevailing fossils, though remains of fish and saurians have been dis- covered—the latter very rarely. ‘The student will do well to spend some days at Cheltenham, whence he will be able to make excur- sions to the chief points of geological interest in the neighbourhood, among which may be mentioned Leckhampton, Crickley, Birdlip, Cold Comfort, Lineover, Cleeve Cloud, Sudeley, and Bredon—all within an easy reach of that town. Further on, in an easterly direction, he may visit the numerous quarries by Andoversford, Naunton, Stow, Stanway, Burford, and Broadway. Southwards he should examine the country in the neighbourhood of Stroud, especially the quarries at Rodborough, Selsby, Painswick, Haresfield, Sheepscombe, and Frocester.
We must now say a few words on a very interesting series of deposits, which we have designated the ‘‘ Ammonite and Belemnite beds” + (“Cephalopoda-bed”’ of Wright), which, though much reduced in thick-
* The entire formation, except where locally affected byfaults, has a gentle dip to the south-east.
+ “On the Basement Beds of the Inferior Oolite in Gloucestershire,’ by the Rey. P. B. Brodie.—Journal of the Geological Society, 1851, p. 208.
BRODIE—GEOLOGY OF GLOUCESTERSHIRE. 87
ness at Leckhampton, may be studied to advantage at Crickley Hill be- tween Cheltenham and Birdlip, at Haresfield, Frocester, and Nailswerth. Below the “ Pisolite ’’ at Crickley is a band of brown, shelly limestone, containing many Ammonites and Belemnites, and a peculiar Tere- bratula (T. cynocephala), which is highly characteristic of this zone. This limestone has been perforated by boring shells, and minute frag- ments of bones and teeth of fish are irregularly dispersed through it, so as to form a kind of bone-bed. At Leckhampton, with the inter- vention only of a few inches of red sandy marl, it reposes on the blue shale of the Upper Lias. At Haresfield and Frocester the basement beds are much thicker and more fossiliferous, and overlie a thick stratum of yellow micaceous sand, from 40 to 60 feet thick, below which the grey marls of the Upper Lias appear. Numerous species of ammonites, belemnites, and other shells, both univalves and bivalves, have been discovered at both these places. The ‘‘ Ammonite bed”’ there is a coarse brown oolitic sandstone, mure or less ferruginous. Although it would be quite out of place in an article like the present to enlarge upon a disputed point as to the true relations of these beds, it is only right to mention that, while some geologists class them with the Upper Lias, others retain them in the Inferior Oolite. Probably the truth lies between the two opinions, and this stage will be found to be really intermediate. At any rate, for the present it must be left an open question, until we obtain further knowledge of the fossils of these deposits in other districts, and are thus able to weigh the evidence in full, and arrive at exactitude.
Viewed from the valley, the outer chain of the Cotswold hills pre- sents a bold line of escarpment, varying in height from 900 to upwards of 1000 feet above the level of the sea. The lower portions present grassy slopes, sinking gently into the plain below, and the upper stand out as bold mural cliffs, for many miles in extent. The hills are often well wooded even to their summits, and their tortuous course from N.E. to S.W. is marked by projecting headlands and deeply- indented bays. There can be no doubt, indeed, that at some remote period the sea occupied this now rich and fertile valley ; and there is evidence in certain drift deposits and ancient shingle beaches at various heights along these hills, to show they were once of much less elevation, and washed by the waves of an ancient inland sea, not inaptly termed the Straits of Malvern.
88 THE GEOLOGIST.
Standing on the top of Leckhampton hill, every one must be struck with the extensive panoramic view, probably unequalled in England, which it commands. The Liassic plain, though flat, is here and there relieved by gentle undulations, and bounded on the west by the fine range of the Malverns, the rounded dome of May Hill, and the hills of the Forest of Dean; while on a clear day a view is obtained of the still more distant mountains of Wales.
There is also another peculiar feature in the physical geography of this district in those outliers or smaller hills which stand out at variable distances from the main chain. These are Robinswood Hill, Church- down, Battledown, Bredon, and others not distinctly visible from Leck- hampton. Though often partially denuded of the oolite, there can be no doubt these isolated spots were formerly united to the Cotswolds, which most probably extended further outwards than they do now.
In addition to Mr. Hull’s “ Geology of the Country around Chelten- ham,”’* and Mr. Lycett’s ‘‘ Cotswold Hills,” we recommend the perusal of Sir R. I. Murchison’s ‘‘ Geology of Cheltenham,” above referred to. Many of the characteristic fossils may be purchased at a moderate rate of Jenkins, a nurseryman, on the right-hand side of the road leading to Leckhampton.
We have necessarily confined our remarks to a limited portion of the geology of a part only of the county of Gloucester ; but this must lead us to wider and more general views of the whole subject—local details and discoveries have their chief value in reference to this end— for which reason we would suggest a comparison of the Oolites in their extension into Somersetshire and Dorsetshire on the one hand, and into Northamptonshire, Lincolnshire, and Yorkshire on the other. Geology, in the subjects of which it treats, requires a liberal and comprehensive view to be taken; and valuable undoubtedly as all local knowledge is, we must not rest satisfied with such a limitation, but carry our investigations into surrounding or into distant regions, and study nature on a grand scale, suitable to the wide fields of observation before us.
* See also Mr. E. Hull’s elaborate memcir on the Physical Geography of the Cotteswold Hills, in the Quarterly Journal of the Geological Society, vol. xi., p- 477.—Eb. or GEoLoaisr.
89
A BRIEF DESCRIPTION OF SOME PLACES NEAR KILLARNEY, OUT OF THE BEATEN TRACK OF ORDINARY TOURISTS: WITH REMARKS ON THE IGNEOUS ROCKS OF THE DIS- TRICT.
By ‘A Brotwer or THE Hamer.”
Reaver, have you ever visited the far-famed Lakes of Killarney? If you have not, by all means go there; and if you are a geologist as well as a lover of beautiful scenery, the pleasure of the visit will be greatly enhanced.
There you have lofty and rugged mountains (some of them clothed with wood nearly to the summit), from whose sides gush limpid foun- tains, increasing in force as they descend, and in their onward course madly leaping down the steep cataracts, until they are at last lost in the majestic lake beneath,-—the admixture and variety of the whole being beautifully harmonized and softened by the extraordinarily luxuriant foliage of thousands of plants, from the stately oak, the bushy arbutus, and dark green holly, to the humble but graceful “‘ London Pride” (Saxifraga umbrosa), the abundance of which seldom fails to attract the notice of the most casual observer.
The mountains are formed of rocks of the ‘‘ old red sandstone period,” the upper division of that group or ‘‘ yellow sandstone” being gene- rally observed at the foot of the slope, this being again overlaid conformably by the ‘‘ mountain-limestone,” which extends in many a contortion over the plain.
In the rocks of the ‘‘old red sandstone”’ a geological eye will at once be struck by the fine examples of glacial action exhibited in the scratches and groovings of their surfaces, caused by the sharp edges of blocks and fragments of other rocks, contained in icebergs, having passed over them; such markings being, for a considerable extent, parallel, or nearly so.
The ordinary visitor to Killarney is generally forced to traverse the same beaten track which hundreds of others have trodden before him. Most people stay for three days only or a week, and during that time are completely at the mercy of hotel-keepers and guides for the disposal of their time; thus losing much both of the picturesque and
90 YHE GEOLOGIST.
of the instructive that is gained by the more adventurous tourist. I would therefore point out one or two places, not more than six or seven miles from that place, which few persons visit, and which none should return home without seeing.
To the east of Killarney, at the foot of the cloud-capped Mangerton, there lies a rocky glen called ‘‘ Glenacappul,”* or the ‘‘ Horse’s Glen.” In it are three little mountain-lakes or “ tarns,” which generally appear as black as ink. The rocks are, the red, green, or grey grits, and slates of the old red sandstone.
On walking down the glen from north to south, the strata are seen bent by numerous contortions, at both the top and bottom of the cliff; but midway, and interstratified with these beds, is a broad band of ‘‘igneous rock,’’ the flexures and folds of which are similar to and coincident with those of the former. This igneous rock is a “ felspathic trap,” or “‘felstone,” and is a compound of felspar and quartz. It is generally of a bluish green or whitish colour, very hard, sometimes containing crystals of white felspar, which, when large and numerous, give it a porphyritic character.
At both the upper and lower surfaces of this band of trap, between it and the sedimentary rock, there are beds of flaky ash, of a green or yellowish green hue.
The massiveness of the rocks, their contortions, the striking ap- pearance of the trap, the stately height of the cliffs, the dark and gloomy waters of the three lakes—all combine in giving an unspeakable grandeur to Glenacappul.
A couple of miles further east, and south of Lough Guitane—a pic- turesque lake situated on the southern side of the mountain-road leading from Killarney to Glenflesk—is another glen, called Cappagh Glen. Its sides are also lofty and rocky cliffs, and the band of trap inter- stratified with the sandstones on its western face presents much the same appearance as that in the Horse’s Glen. Both in form and size the two glens are much alike; but the wildness of the latter (in which patches of heath and a few ferns alone are seen) is com- pletely softened down in the former by the luxuriance of the natural wood, principally oak and holly, the abundance and size of the different species of ferns—from the lofty ‘“ Brake’’+ (Pteris
* Cappul, Irish for “ horse.” { This fern grows here to a height of more than ten feet.
GEOLOGICAL NOTES ON KILLARNEY. 91
aquilina), and ‘‘Osmunda regalis”—to the charming little Hymeno- phyllum, with which the rocks are covered, and by the rich green pasture of the alluvial flat through which the murmuring rivulet flows.
Here, in the heights, the eagle builds her nest, and hardy and active must he be that would attack her stronghold ; here the red deer, ‘‘antlered monarch of the waste,” strays at his pleasure, with nought to alarm him but the voice of the distant herdsman when driving home the cattle at eventide.
A little east of Cappagh glen, and parallel to it, is a deep ravine or cleft in the mountains. It is separated from the former by a trappean hill, called Benaunmore. This hill is principally a mass of greenish felstone, traversed in several places by dykes, on the east side of which, viewed as you proceed southwards up the ravine, the rock assumes a prismatic structure, caused by joints which fashion it into columns, some of which are upwards of 200 feet in height. Their shape is usually that of a five- or six-sided prism, and they extend for nearly a mile, in one or two places being cut across by dykes of white felstone.
This peculiar structure, and the great height of the columns, par- ticularly when seen towering above the little lake called Lough Nabroda, give a most impressive appearance to the spot.
Eastwards from this, wherever the trap is associated with the sedi- mentary rocks, it appears to be interstratified with them.
The hill of Benaunmore gives the idea of its having been the focus or volcanic centre whence the ancient molten matter was ejected, and flowed over the bed of the primeval sea in all directions. The aqueous deposits went on again over this mass, and eventually the whole was lifted up from the ocean-bed, and left in its present position.
Could there be a wider contrast than that between the present con- dition of the peaceful Cappagh, abounding in animal and vegetable life, and the time when it lay in the depths of a gloomy sea, whose waters, rendered noxious by the quantity of iron which they contained, suffered not the existence of animal life,* and but little or no vegetation—when the only thing that broke in upon the monotony of this watery wilder- ness was the hissing stream of molten mineral matter, so intensely heated that it flowed for miles before it cooled!
* No fossils of any kind have hitherto been discovered in the old red sandstone of this locality.
92 THE GEOLOGIST.
The places I have mentioned are accessible to the tourist ; who, if he has to use a little extra exertion in reaching them, will assuredly consider himself well repaid for having done so.
THE COMMON FOSSILS OF THE BRITISH ROCKS. By S. J. Macxtr, Esa., F.G.S., F.S.A., &e., &e.
CHAPTER II.
The Rocks—their Order and their Teachings.
(Continued from page 64.)
Tur unstratified Plutonic rocks are considered to form, as we have intimated, the common base of the stratified beds all over the globe. With them, however, we have little to do in this place. Our labours commence with the stratified, and we should even have excluded the so- called ‘‘ Azoic,” had not that term been recently subjected to con- siderable restriction by the discovery of organic remains in some of its members ; and, as it is still likely, by further researches, to be totally absorbed into the Paleozoic system, we append an ideal section representing the sequence of formation of the most ancient groups of fossiliferous rocks, with the relative position of those primordial con- glomerates, flags, and schists in which as yet no organic remains have been found. Whether, at the vastly remote period at which those isolated masses, still ranked as Azoic, were formed, the advent of life had really not taken place on our planet, or whether those masses are the few remnants of a still older stage of our world than any presented to us by the recognised series of fossiliferous rocks, has yet to be determined by the investigations of geologists—but in their massiveness and their vast age they must ever be regarded with veneration and wonder.
The ordinary diagrams or ideal vertical sections of the superposition of the rocks have engendered to a great extent unnatural and erroneous ideas of proper sequence, and has led to a prevalent impression that the strata were deposited horizontally over each other, like books stacked