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great continent lies beyond, which has still to be appropriated, fills the traveler with cheering thoughts and sanguine hopes. He may be reminded that there is another side to the picture, that where the success has been so brilliant, and where large fortunes

have been hastily realized, there will be rash speculations and bitter disappointments; but these ideas do not force themselves into the reveries of the passing stranger. He sees around him the solid fruits of victory, and forgets that many a soldier in the foremost ranks has fallen in the breach; and cold indeed would be his temperament if he did not sympathize with the freshness and hopefulness of a new country, and feel as men past the prime of life are accustomed to feel when in company with the young, who are full of health and buoyant spirits, of faith and confidence in the future."

The second chapter is filled with a full and most interesting description of Niagara, its historical connections, and its geological features. We wish every one visiting that sublime spectacle could have the vision of the philosophical inquirer before us. An involuntary ejaculation, accompanied with a wondersome stare, do not now express the emotions of an intelligent beholder. With the boldness of a practiced flight, a mind disciplined to climb the heights of philosophical and scientific reasoning becomes absorbed in the contemplation of facts having an intimate relation to other facts which are bound by an indissoluble chain in the great circle of universal truths. Our limits do not permit us to give the whole chapter: a bare notice must suffice.

With unwearied diligence Mr. Lyell seems to have collected specimens from various localities which satisfy him, beyond a doubt, that a retrocession has been going on in the Falls, and that they are now situated at a point seven miles distant, in a southerly direction, from their hypothetical locality at Queenstown. Bakewell, another eminent English geologist, who has examined the Falls, computes the rate of retrocession at about a yard annually; but Mr. Lyell hazards the estimate of a foot per year, which would consume a period of thirty-five thousand years for its accomplishment.

Here we have a broad avowal of a principle in geological science which grates harshly on the ears of those whose faith in the Mosaic record leads them to assign a period of only six thousand years to the earth's existence. It is one which involves criticism of too deep and

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prolonged a character for our present paper, and we avow no definite opinion-if, indeed, an opinion really definite could be formed. Too much scope given to Biblical criticism in connection with the Mosaic cosmogony, would lead us all into a mysticism of figures since no multiplied number of ages would suffice for the materialist who contends for the eternity of the world; and too rigid an adherence to the literal interpretation of the Mosaic record would involve the defender of truth, be his piety never so ardent and his faith in the revealed Word into a greater difficulty than the intervennever so strong, as well as his opponent, tion of an intruded dyke would be to the explorer after rich veins of ore. We are disposed to check this spirit of making illimitable drafts upon eternity for the sake of assigning a period for the evolution of some physical change, or the peopling of some sea, estuary, or continent, with marine or terrestrial fauna. An adherence to closer limits will tend, we think, to concentrate, rather than diffuse, the perceptions and reasonings of geologists, and the more speedily lead them to accurate results.

Be this as it may, we are satisfied that Geology, as a science, with its array of facts and inductions, has been too early brought into the field of theological polemics. Before Geology had assumed its form as an embryo, Burnet, in 1690, and Whiston, in 1696, published treatises or "Sacred Theories of the Earth, wherein the accounts of the Holy Scriptures are shown to be consistent with Reason and Philosophy," &c.; and from that time to this Buffons and Whistons, and Voltaires and Bucklands, have sought to avail themselves of every new fact brought to light by a Lehman, a Werner, a Smith, a Hutton, a Cuvier, a Humboldt, or a Lyell, in confirmation of their own views and annihilation of the opposing doctrines. Had some of them come up to us ossified or silicified from some almost unknown abyss of the cretaceous or carboniferous series, we trow they would have rendered nobler service to science and to truth than by speculations on isolated facts, culled in the infancy of a most manly and invigorating and attractive department of human knowledge. Let it be said to our professors and students-observe more and write less, think deeper and talk less vauntily and develop more extensive generalizations of facts, instead of centering the mind on a prejudged and prefavored

idea. Do this, and science will be more nobly served, and more rapidly advanced than by ardent efforts to establish either theoretical systems or nomenclatural schools.

One of the best features of this book is, that it does thus furnish the bases of comparison between American and European strata and series, by an accurate and eminent observer. An instance of this we notice with reference to the Nova Scotia coal fields, four-fifths of the fossil plants being identified with European species. Although many instances might be quoted in evidence, we confine ourselves to these two, taken at random :

"I was desirous of ascertaining whether a generalization recently made by Mr. Logan in South Wales could hold good in this country. Each of the Welsh seams of coal, more than ninety in number, have been found to rest on a sandy clay or firestone, in which a peculiar species of plant called Stigmaria abounds, to the exclusion of all others. I saw the Stigmaria at Blossberg, lying in abundance in the heaps

able to identify 23 out of 147 with living shells. This relation of the fossil and recent fauna had already led Mr. Conrad and the Professors Rogers to the same conclusions, and they had correctly called these deposits Miocene. Fourthly, the corals, of which I obtained thirteen species, agree all generically with those of the Miocene beds lite, the same as one from the Suffolk crag, of Europe, and some specifically, as a lunuand Anthophyllum breve, common in the faluns of Touraine. Fifthly, the cetacea also agree generically, and the fish in many cases specifically, with European Miocene fossils, and no remains of reptiles have been found on either side of the Atlantic in this formation."

It was for a long time disputed, and is still doubted by many intelligent men, whether coal is of vegetable origin. To our own minds nothing can be more clear and satisfactory than is the evidence upon this point, and as it is one of much importance, and the topics introduced by Mr. Lyell are illustrated by recent facts of his own observation, we give it some

of rubbish where coal had been extracted scope:
from a horizontal seam. Dr. Saynisch,
president of the mine, kindly lighted up
the gallery that I might inspect the works,
and we saw the black shales in the roof,
adorned with beautiful fern leaves, while
the floor consisted of an under-clay, in
which the stems of Stigmaria, with their
leaves or rootlets attached, were running
in all directions. The agreement of these
phenomena with those of the Welsh Coal-
measures, 3000 miles distant, surprised me,
and lead to conclusions respecting the ori-
gin of coal from plants not drifted, but
growing on the spot, to which I shall refer
in the sequel."

On p. 109, speaking of the Miocene fossils of Williamsburg, (Va.), he says:

"I procured 147 species of shells, exclusive of Balani and corals, from this formation in the United States, and chiefly during the present expedition, and near the banks of the James River.

"That they belong to the same age as the Miocene deposits of Europe may be inferred-first, from their position, as they overlie the Eocene marls containing shells, resembling those of the London and Paris basins-secondly, from the close affinity of many of the abundant species to fossils of the crag of Suffolk and the French faluns:-thirdly, from the proportion of the fossil shells, identical in species with mollusca, now inhabiting the American coast, the proportion being about one-sixth of the whole, or about seventeen per cent., in those compared by me, for I have been

"In this coal field, (Pottsville) as in all others hitherto observed in America, particular seams of coal are found to be far more persistent than the accompanying beds of shale, sandstone, or limestone. As we proceeded from Pottsville, by Tamaqua, to the Lehigh Summit Mine, we found the beds of grit and shale gradually to thin out, so that several beds of anthracite, at first widely separated, were brought nearer and nearer together, until they united, and formed one mass about fifty feet thick, without any greater interpolated matter than two thin layers of clay with Stigmariæ. At Mauch Chunk, or the Bear Mountain, this remarkable bed of anthracite is quarried in the open air, and removed bodily together with the overlying sandstone, forty feet thick, the summit of the hill being "scalped," as one of the miners expressed it. The vegetable matter, which is represented by this enormous mass of anthracite, must, before it was condensed by pressure and the discharge of its hydrogen, oxygen, and other volatile ingredients, have been probably between 200 and 300 feet thick. The accumulation of such a thickness of the remains of plants, so unmixed with earthy ingredients, would be most difficult to explain on the hypothesis of their having been drifted into the place they now occupy; but it becomes intelligible if we suppose them to have grown on the spot. Whether we regard the Stigmariæ as roots, according to the opinion of M. Adolphe Brongniart and Mr. Binney, or embrace the doctrine of their being

aquatic plants, no one can doubt that they at least are fossilised on the very spot where they grew; and as all agree that they are not marine plants, they go far to establish the doctrine of the growth in situ of the materials of the overlying coal

seams.

"A few days' observation of the identity of the fossil plants, and the relative position of the anthracite, satisfied me that it was of the same age as the bituminous coal which I had seen at Blossberg. This opinion was, I believe, first promulgated by Mr. Featherstonehaugh, in 1831, at a time when many geologists were disposed to assign a higher antiquity to the anthracite than to the bituminous coal-measures of the United States. The recent surveys have now established this fact beyond all question, and hence it becomes a subject of great interest to inquire how these two kinds of fuel, originating as they did from precisely the same species of plants, and formed at the same period, should have become so very different in their chemical composition. In the first place, I may mention that the anthracite coal-measures above alluded to, occurring in the eastern or most disturbed part of the Appalachian chain, are fragments or outliers of the great continuous coal field of Pennsylvania, Virginia, and Ohio, which occurs about forty miles to the westward. This coal field is remarkable for its vast area, for it is described by Professor H. D. Rogers as extending continuously from N. E. to S. W. for a distance of 720 miles, its greatest width being about 180 miles. On a moderate estimate, its superficial area amounts to 63,000 square miles. It extends from the northern border of Pennsylvania as far south as near Huntsville in Alabama.

"This coal formation, before its original limits were reduced by denudation, must have measured, at a reasonable calculation, 900 miles in length, and in some places more than 200 miles in breadth. By refer ence to the section (fig. 5, p. 74,) it will be seen that the strata of coal are horizontal to the westward of the mountain in the region D, E, and become more and more inclined and folded as we proceed eastward. Now it is invariably found, as Professor H. D. Rogers has shown by chemical analysis, that the coal is most bituminous towards its western limit, where it remains level and unbroken, and that it becomes progressively debituminized as we travel southeastward towards the more bent and distorted rocks. Thus, on the Ohio, the proportion of hydrogen, oxygen, and other volatile matters, ranges from forty to fifty per cent. Eastward of this line, on the Monongahela, it still approaches forty per cent., where the strata begin to experience some gentle flexures. On entering the Alleghany Mountains, where the distinct an

ticlinal axes begin to show themselves, but before the dislocations are considerable, the volatile matter is generally in the proportion of eighteen or twenty per cent. At length, when we arrive at some insulated coal fields (5, fig. 5,) associated with the boldest flexures of the Appalachian chain, where the strata have been actually turned over, as near Pottsville, we find the coal to contain only from six to twelve per cent. of bitumen, thus beconing a genuine anthracite. (Trans. of Ass. of Amer. Geol., p. 470.)

"It appears from the researches of Liebig and other eminent chemists, that when wood and vegetable matter are buried in the earth, exposed to moisture, and partially or entirely excluded from the air, they decompose slowly and evolve carbonic acid gas, thus parting with a portion of their original oxygen. By this means, they become gradually converted into lignite or wood-coal, which contains a larger proportion of hydrogen than wood does. A continuance of decomposition changes this lignite into common or bituminous coal, chiefly by the discharge of carburetted hydrogen, or the gas by which we illumine our streets and houses. According to Bischoff, the inflammable gasses which are always escaping from mineral coal, and are so often the cause of fatal accidents in mines, always contain carbonic acid, carburetted hydrogen, nitrogen, and olifiant gas. The disengagement of all these gradually transforms ordinary or bituminous coal into anthracite, to which the various names of splint coal, glance coal, culm, and many others, have been given.

"We have seen that, in the Appalachian coal field, there is an intimate connection between the extent to which the coal has parted with its gaseous contents, and the amount of disturbance which the strata have undergone. The coincidence of these phenomena may be attributed partly to the greater facility afforded for the escape of volatile matter where the fracturing of the rocks had produced an infinite number of cracks and crevices, and also to the heat of the gases and water penetrating those cracks, when the great movements took place, which have rent and folded the Appalachian strata. It is well known that, at the present period, thermal waters and hot vapors burst out from the earth during earthquakes, and these would not fail to promote the disengagement of volatile matter from the carboniferous rocks."

On page 197, in speaking again of the anthracite, Mr. Lyell makes the following statement, which furnishes the results of experiments made by a careful analyst:

"I have already mentioned, (p. 72.) that

in crossing from the west of the Alleghany mountains to the eastern portion of the Appalachian coal field the volatile ingredients (oxygen, hydrogen, and nitrogen,) of the original coal bear continually a smaller and smaller proportion to the carbon. In the specimens which I myself obtained from Pomeroy, Ohio, where the coal is bituminous, and where the strata are undisturbed, the quantity of gaseous matter has been found by my friend Dr. Percy to be in the proportion of 19 per cent., the rest being carbon and ash. 2dly. In the coal at Frostburg, in Maryland, in the midst of the Alleghany chain, where the strata have undergone but slight disturbance, the proportion of volatile matter was found to be 9 per cent. 3dly. In the Pennsylvanian anthracite of the Lehigh and Mauch Chunk mines, before alluded to (p. 69), the volatile ingredients are about 5 per cent."*

In Chap. VII. Mr. Lyell gives a fine description of the "Great Dismal," that very singular and prominent object of interest to the observer of physical phenomena. It requires no great flight of imagination in the mind of the student to see, in this archetype of the ancient coal-deposits, a volume of our own age in which is practically illustrated the changes and the history of those immense repositories which have become of such importance in the economy of civilized society. Mr. Lyell thus speaks on p. 118:

"That the ancient seams of coal were produced for the most part by terrestrial plants of all sizes, not drifted, but growing on the spot, is a theory more and more generally adopted in modern times, and the growth of what is called sponge in such a swamp, and in such a climate as the Great Dismal, already covering so many square miles of a low level region bordering the sea, and capable of spreading itself indefinitely over the adjacent country, helps us greatly to conceive the manner in which the coal of the ancient Carboniferous rocks may have been formed. The heat, perhaps, may not have been excessive when the coal measures originated, but the entire absence of frost, with a warm and damp atmosphere, may have enabled tropical forms to flourish in latitudes far distant from the line. Huge swamps in a rainy climate, standing above the level of the

surrounding firm land, and supporting a dense forest, may have spread far and wide, invading the plains, like some European peat-mosses when they burst; and the frequent submergence of these masses of vegetable matter beneath seas or estuaries, as often as the land sunk down during subterranean movements, may have given rise to the deposition of strata of mud, sand, or limestone, immediately upon the vegetable matter. The conversion of successive surfaces into dry land, where other swamps supporting trees may have formed, might give origin to a continued series of coalmeasures of great thickness. In some kinds of coal, the vegetable texture is apparent throughout under the microscope; in others, it has only partially disappeared; but even in this coal the flattened trunks of trees of the genera Lepidodendron, Sigillaria, and others, converted into pure coal, are occasionally met with, and erect fossil trees are observed in the overlying strata, terminating downwards in seams of coal. The chemical processes by which vegetable matter buried in the earth is gradually turned into coal and anthracite has been already explained. (See above, p. 72.)

"Before concluding the remarks which are naturally suggested by a visit to the Great Dismal, I shall say a few words on a popular doctrine, favoured by some geologists, respecting an atmosphere highly charged with carbonic acid, in which the coal plants are supposed to have flourished. Some imagine the air to have been so full of choke-damp during the ancient era alluded to, that it was unfitted for the respiration of warm-blooded quadrupeds and birds, or even reptiles, which require a more rapid oxygenation of their blood than creatures lower in the scale of organization, such as have alone been met with hitherto in the Carboniferous and older strata. It is assumed that an excess of oxygen was set free when the plants which elaborated the coal subtracted many hundred million tons of carbon from the carbonic acid gas, which previously loaded the air. All this carbon was then permanently locked up in solid seams of coal, and the chemical composition of the earth's atmosphere essentially altered.

"But they who reason thus are bound to inform us what may have been the duration of the period in the course of which so much carbon was secreted by the powers

"These results were obtained from an elaborate analysis made for me by the kindness of Dr. J. Percy, of Birmingham, since the statement given at p. 72 was printed. They bear out the geological inferences, there referred to, of Professor H. D. Rogers; but it will be seen that the proportions of the chemical constituents differ greatly, the gaseous matter being only half the previously estimated quantity. For details of the analysis and manipulations, see Appendix to a paper by the author, in the Journal of Geol. Soc. London, No. II., 1845."

of vegetable life, and, secondly, what accession of fresh carbonic acid did the air receive in the same. We know that in the present state of the globe, the air is continually supplied with carbonic acid from several sources, of which the three principal are, first, the daily putrefaction of dead animal and vegetable substances: secondly, the disintegration of rocks charged with carbonic acid and organic matter; and, thirdly, the copious evolution of this gas from mineral springs and the earth, especially in volcanic countries. By that law which causes two gases of different specific gravity, when brought in to contact, to become uniformly diffused and mutually absorbed through the whole space which they occupy, the heavy carbonic acid finds its way upwards through all parts of the atmosphere, and the solid materials of large forests are given out from the earth in an invisible form, or in bubbles rising through the water of springs. Peatmosses of no slight depth, and covering thousands of square miles, are thus fed with their mineral constituents without materially deranging the constituents of the atmosphere breathed by man. Thousands of trees grow up, float down to the delta of the Mississippi and other rivers, are buried, and yet the air, at the end of many centuries, may be as much impregnated

with carbonic acid as before.

"Coral reefs are year after year growing in the ocean-springs and rivers feed the same ocean with carbonic acid and lime; but we have no reason to infer that when mountain masses of calcareous rock have thus been gradually formed in the sea, any essential change in the chemical composition of its waters has been brought about. We have no accurate data as yet for measuring whether, in our own time, or at any remote geological era, the relative supply and consumption of carbon in the air or the ocean causes the amount of those elements to vary greatly; but the variation, if admitted, would not have caused an excess but rather a deficit of carbon in the periods most productive of coal or peat, as compared to any subsequent or antecedent epochs. In fact, a climate favoring the rank and luxurious growth of plants, and at the same time checking their decay, and giving rise to peat or accumulations of vegetable matter, might, for the time, diminish the average amount of carbonic acid in the atmosphere-a state of things precisely the reverse of that assumed by those to whose views I am now objecting."

The carboniferous series of our country seem to have been a prominent object of attention, and the particularity with which the details are given will afford much instruction to those readers who have not made themselves acquainted with the re

sults of either individual enterprise or geological surveys. In fact, were we to indicate a small portion even of the varithe selection would extend our notice ous phenomena of which notice is made, much beyond its proper limits.

We are obliged to pass by this topic without sketching the explorations in the Nova Scotia coal field, where many facts of a valuable character were noted, and are recorded by the tourist with his usual acumen and discrimination. Chapter XXIV., of the second volume, will be found unusually interesting in this particular feature. The beds through which the fossil trees are dispersed have a thickness of 2500 feet. In the vicinity of Minudie the strata form a cliff having a vertical height of 150 to 200 feet, in which Mr. Lyell noticed a fossil tree twenty-five feet high and four feet in diameter.

We want just such observers as Mr. Lyell-men who have traveled extensively over those portions of Europe which may safely be regarded, from their importance and richness in the fossil flora and fauna, as the basis of comparison in more extended research. This accumulation of facts which now lie, literally, buried in the earth, the attracting to this work of indefatigable and devoted students, the developing of the vast resources of our western continent, the faithful, and earnest, and ardent elaboration of a slow but surely growing system of physical truth, is measurably but just begun. We hope for a brighter day, and we look upon the circulation of Mr. Lyell's tour as a favorable stimulus in this work.

But not only in a scientific view must this book be regarded as an acquisition to the library of American readers. That it will be highly esteemed in Great Britain we have not the slightest doubt: it stands in the very highest rank of enlightened observation and criticism. We should scarcely be doing justice to the work to dismiss it without one or two extracts indicative of the liberal spirit of the author.

On page 57 he thus notices the politeness to ladies, so characteristic of the American people:

strike a foreigner in the United States is "One of the first peculiarities that must the deference paid universally to the sex, without regard to station. Women may travel alone here in stage-coaches, steamboats, and railways, with less risk of encountering disagreeable behavior, and of

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