Page images
PDF
EPUB

a

a

with such a bare hypothesis, if it had not already awakened the curiosity of many to a class of facts extremely interesting, although too few. in number to admit as yet of extensive generalization. The uniformity of ancient climate can only be established when scientific researches shall have been further prosecuted in every zone, from the territories of our new allies the Esquimaux, to the southern boundaries of our Indian empire.

Before we finally take leave of organic remains, we must not forget that Professor Buckland has in this volume made particular mention of the first example of a mammiferous quadruped occurring in an ancient secondary rock. The remains of land quadrupeds had never before been observed in

any

formation so ancient as the chalk: but in the calcareous slate of Stonesfield in Oxfordshire, which lies in the upper part of the lowest division of colitic rocks, Dr. Buckland notesTwo portions of the jaw of the Didelphis or Opossum, being of the size of a small kangaroo rat, and belonging to a family which now exists chiefly in America, Southern Asia, and New Holland .... I refer (he adds) the fossil in question to this family on the authority of M. Cuvier who has examined it.'

As this fact is completely at variance with all preceding observations, it is not surprizing that it has been received with some scepticism. M. Constant Prevost,* who has himself visited Stonesfield, has lately published a memoir, in which every argument that can be urged to invalidate Dr. Buckland's opinion is put forth with great ability and with a spirit of fairness; but all this has not in the least shaken our reliance on the accuracy of the statement. In the first place, it is admitted that the remains in question were decidedly imbedded in the Stonesfield slate. To this stratum, ' in working the quarries at Stonesfield, they descend by vertical shafts through a solid rock of corn-brash and stratified clay more than forty feet thick.'t M. Cuvier, who has re-examined the fossil in question since the objection was started, still pronounces the animal to have been mammiferous, resembling an opossum, although of an extinct genus, and differing from all known carnivorous mammalia in having ten teeth in a series in the lower jaw. M. Constant Prevost remarks, 'that the relations of the slate in question, both with the superincumbent and subjacent beds, are obscure at Stonesfield; that doubts have been expressed by different English writers as to the exact position it occupies among the minor subdivisions of the oolitic series; that the schistose oolitic rocks, supposed by Dr. Buckland and other English geologists

Observations sur les Schistes calc. colit. de Stonesfield. Ann. des Sciences Nat. April, 1825. 7 p. 393. VOL. XXXIV. NO. LXVIII.

L L

to

to belong to the same formation, and said to extend across England, from Coly-Weston near Stamford in Lincolnshire to Hinton near Bath, and in many places extensively quarried for coase dolitic slate used for covering houses,'* may perhaps be incorrectly referred to the Stonesfield strata,' for they do not agree precisely in all their mineralogical characters, nor contain in any other loca- . lity the same singular assemblage of organic remains as at Stonesfield.'-As, however, the French geologist has not visited these various localities, he is incapable of appreciating the weight of one description of evidence which has powerfully intuenced the minds of English observers. The eye can often recognize resemblances between different rocks in regard to their colour, texture, mode of aggregation, and the general physiognomy of the entire group of strata, quite as incapable of description as are those features of the human countenance that sometimes constitute the strongest likeness between individuals. Now the importance attached to these minute correspondences is not of a fanciful or delusive kind: for although crystalline rocks of widely different ages may often be identical in composition and external character, because their aggregation may be regulated by the fixed laws of chemical combination, yet, in rocks of sedimentary origin, an exact coinciderice in the particulars before alluded to, in conjunction with considerable similarity of fossil contents, can scarcely arise from any other cause than contemporaneous deposition from the same fluid; and if, in addition to numerous circumstances of this kind, there are grounds, as in the case of the Stonesfield slate, for presuming the constant relation of certain other rocks always contiguous in the different localities, it is inconceivable that accidental or independent causes could have occasioned such results. But we have moreover to inquire, if the Stonesfield slate be not referable to the oolitic formation, wbat place can be assigned to it in the series? The hypothesis hinted at by M. Prevost to relieve us from this dilemma, although ingenious, is evidently so unsatisfactory, even to himself, that we shall not stay to comment upon it, but proceed to consider whether the remains of Stonesfield are really so anomalous as is imagined, and whether the unwillingness on the part of continental naturalists to receive the facts coinmunicated by Dr. Buckland has not far exceeded the bounds of reasonable caution.

The abundance of fossil wood in the lias and oolite has always warranted the conclusion, that continents existed at the time of their deposition. That the rivers of those continents floated down not only wood, but occasionally animals drowned on their banks, Thellusson, who in bis will' directed the produce of his estates, both real and personal, to the amount of about 800,0001., to be accumulated and laid out in land, during (in effect) the lives of all his descendants, however numerous and remote, who should be living at his death. At theend of that period, the estates, as well devised as directed to be purchased, were to be divided in lots between the eldest male lineal descendants, then living, of his three sons. The trust, after having been contested in chancery, and on appeal in the lords, was finally established, and is in operation while I write ; but it occasioned an act restrictive of accumulation, which will be noticed hereafter.

* Observations sur les Schistes calc. oolit. de Stonesfield. Aun, des Sciences Nat. April, 1825, p. 393.

AS

• The rule, however, is still in full force as to capital. In its defence it is often urged, that all the candles are burning at the same time. Luminous as may be the illustration, it is somewhat defective in exactness: the candles are of equal length-but among a number of lives selected, a few will probably occur who far outlive the ordinary period of mortality. So calculate the life insurance companies; and so did the testator, or bis legal adviser, in a cause of Bengough v. Edridge, which now awaits the judgment of the Vice-Chancellor, on the following singular will, which I shall cite somewhat at length, as strongly illustrative of the extent of perversion to which the defective terms of the rule in question

exposes it. The object of an opulent testator, who had no issue, was to give his landed estates, and those which might be purchased with their produce during twenty-one years (the period still allowed by law for accumulation), to his collateral relations, consisting of five nephews and grandnephews, a niece and a grandniece, and their several male de scendants, for successive life-interests, as far as the restrictions of the law against perpetuities would allow. For this purpose, all such estates were vested, and directed to be vested, in fee-simple, in trustees, who were to hold the same for a period of 120 years from the testator's death, if twenty-eight persons therein named (of whom the first seven were the above relations, and the other twenty-one strangers), or any of them, shall so long live ; and then for a further period of twenty years, from the determination of the first term. These terms were intended as nearly commensurate with the periods during which estates might be tied up: viz. any lives in being and twenty-one years ; and might be termed the machinery of the contrivance. Then followed its working, or the beneficial interests carved out of the terms. They consisted in a series of trusts for a term of ninety-nine years, if each successive donee should so long live, for the nephews, greatnephews, niece, and grandniece named, and the respective heirs male of their bodies in succession, forming, in effect, successive estates for life; and finally, failing the whole of these, for the individuals successively answering the description of the testator's right beirs, during similar derivative and determinable terms of ninety-nine years each, until the above technical terms of 120 years and twenty years should be exhausted, either by lapse of time, or the deaths of all the nominees. As to the reversion expectant on the above two terms of 120 years and twenty years, testator directs it to be conveyed on the determination of these two terms, and not before, to his nephews and greatnephews, niece and greatniece before specified, and their respective issue inale, in the like order of succession in a course of MM 4

strict

[ocr errors]

all those of Cuckfield, are terrestrial, lacustrine or fluviatile. We have not sufficient information concerning the bones, teeth, and palates of the various fishes and sharks to decide that any two of them agree in species. This remark applies with still greater force to the remains of cetacea and birds. No Didelphis has yet been found in the Tilgate beds, no Iguanodon at Stonesfield. That the bones of gigantic dimensions procured at Cuckfield belong strictly to the same genus as the Megalosaurus of Stonesfield, we have little doubt, although the bones of the skeleton bitherto found in actual apposition at either place are so few, that to determine this point, much less to decide on their specific identity, is impossible. The same may be said of the Plesiosaurus and Crocodile. : Although the tortoises, are numerous in both localities, none have yet been shown to be of the same species. The correspondence, in short, of the remains at Stonestield and Tilgate Forest, imbedded in strata totally dissimilar in mineralogical characters, is what we might expect to find between the same formations and the deltas of the Nile, Ganges, and all large rivers of the present day in hot climates.

We have only space to allude briefly to some of the geological papers in this volume. They contain a great mass of new information, and we cannot but express our regret that the Geological Society, possessing so many zealous members, and engaged in promoting a science so fertile in new discoveries, should have permitted a lapse of two years to intervene between the comple. tion of the volume we have been reviewing, and a new part, published wbilst we are concluding this Article. There are two papers by Mr. Colebrooke on the valley of the Sutluj river, in the Himalaya mountains, and on the north-eastern border of Bengal, and another by Mr. Fraser on the country between Delhi and Bombay, which, when considered together, are sufficient to establish a remarkable resemblance in the leading geological features of the vast continent of India to that of Europe and North America. The primary rocks in Central India and in the Himalaya mountains are identical in mineralogical character with those of the Alps, and, in fact, of all primary ranges in the world. The striking analogy of the fossils from the north-east of Bengal to those of the formations above the chalk in England, is extremely curious, and quite consistent with the conclusions already deduced from the organic remains procured in the strata near Madras, and deposited with specimens from various parts of India in the museum of the Geological Society. The identity of the basalts and amygdaloids, and other varieties of trap brought by Mr. Fraser from India, with those found in similar situations in England, is no less interesting; and lastly, the coal formation,

consisting

consisting of micaceous sandstone, bituminous shale and coal, on the banks of the Tista and Subuk rivers, which descend from the Bhotan mountains, cannot fail to recal to the mind of the geologist the ancient coal formations of Europe and North America,

The joint paper on the south-western coal district of England, by Dr. Buckland and Mr. Conybeare, deserves attention no less for the variety than the importance of its contents. It establishes the relations of some of the most remarkable British rocks, and furnishes us with an accurate description of the physical geography of a large district. It may also be regarded as a statistical document of the first authority, containing numerous detailed sections of collieries and a determination of the limits of the coal fields of Bristol, the Forest of Dean, and several of minor extent, by which their present productive powers and future resources may be estimated; lastly, it supplies data, founded on multiplied observations, which may direct the search of the miner to new discoveries, and often prevent a fruitless expenditure of capital in unsuccessful trials. The Bristol coal district, illustrated by the beautiful map and sections accompanying this memoir, may be pointed out to the student as full of instruction, for a great variety of formations are here comprized within a small space; and,

; while a knowledge of their regular order of superposition may:

7:be easily obtained, instructive examples occur of the occasional absence of different members of the series and of the leading features of disturbance exhibited on so immense a scale in high mountain chains. We regard this country also as the more entitled to the student's preference, because trap rocks, so abundant in the coal fields of Scotland and the north of England, are here entirely wanting, at least in every formation from the old red sandstone to the oolite inclusive. Geologists have in general commenced their investigations in countries where the derangement of the strata was greatest, and all the phenomena attending them the most complicated. They have studied the exceptions before the rule; and when to this we add disregard to the present operations of nature, whether with reference to aqueous deposits or volcanic products, we cannot be surprized that the theories of the earlier professors of this science, even when founded exclusively on facts and observations, were contradictory; and that the generalizations of Werner and Hutton, though bearing impressed upon them the decided marks of genius, have required considerable modifications.

Two great series of rocks occupy the south-western coal district. In the first, comprizing the lowest and most ancient formations, (the grey wacke transition limestone, old red sandstone, mountaiw limestone and coal measures,) the strata are highly inL L 3

clined,

a

« PreviousContinue »