position above and below each other. I have continually endeavoured to leave out the consideration of Organic Remains, though it was impossible to do so entirely. But it appeared probable that, for general readers, the method of surveying the two lines of evidence apart, might be the more favourable to a correct apprehension of the whole. We must, therefore, now direct our attention to the attractive department of Geology, to which the name of Palæontology has been appropriated.

In all the terrene formations till we reach the very early ones, we are met by the remains of creatures which once had life, and were furnished by their Creator with the means of performing functions and enjoying life to the extent of their capacities. In some of the strata, the number is comparatively small; but in the greater part it very considerable.

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The first systems of stratification, gneiss, mica schist, and so on to the lower part of the Cambrian beds, supply no vestiges of vegetable or animal life. But it would be unwarrantable to affirm absolutely that living creatures had no place in the waters which once covered those rocks, and from which they were deposited; for the heat propagated from below, through the substance of the granitic masses, and which has given a partially fused and crystalline character to the gneissic, would be effectual to dissipate all organized matter, had such existed before the high temperature was produced.

In a citation before given from Professor Phillips* we have contemplated a sketch of the forms of organic life from the earliest appearance in the slate-mountains of North Wales and Cornwall, to those of the present creation. To have the mind duly impressed by a view at all approaching to completeness of the little that is known, the study of many geological works, a familiar acquaintance with

* Pages 81-84.

collections, and an actual inspection of the rocks themselves, are, if not necessary, yet highly desirable. The first and second of these means are all that many studious persons can command; but for them let us be thankful, and by the use of them we may acquire the qualifications which are indispensable for enjoying the survey of nature upon a grand scale, whenever it may be put into our power.

The earliest appearances of life are two or three species of zoophytes, and casts (that is, impressions in mineral matter remaining after the organized substance has been dissolved and washed away,) of several species of shells which have been discovered in the slate-rocks just mentioned. The structure of those shells shews that their inhabitants stood higher in the scale of organization than our cockles and oysters. But we should not be warranted in supposing that these, should we call them twenty or thirty species, were the whole amount of the kinds of living creatures at that remote era. It is a wonder that any have escaped total obliteration. Besides these few corallines and hard shells, there might be many species of many animal orders, the remains of which have been entirely decomposed and absorbed. The fossils referred to are arranged along the surfaces of deposit, in such positions and regularity as shew that the animals lived and died on the spots which have preserved their remains. An indication is thus afforded of the lapse of time, which is very impressive. An area of soft clay at the bottom of a primeval ocean was deposited, and received its living tenants with their shelly habitations; from their first creation growing up to the preservation of individual life, increasing and multiplying their kinds, and generation succeeding generation till the species becomes extinct. Though perfect knowledge is not possessed, yet there are reasons for

By the late Rev. John Josias Conybeare, the Rev. Prof. Sedgwick, and Prof Phillips.

believing that the duration of life to testacean individuals of the present races is several years. But who can state the proportion which the average length of life to the individual mollusc or conchifer, bears to the duration appointed by the Creator to the species?-Take any one of the six or seven thousand known recent species. Let it be a Buccinum, of which 120 species are ascertained, (one of which is the commonly known whelk;) or a Cypræa, comprising about as many, (a well-known species is on almost every mantel-piece, the tiger-cowry;) or an Ostrea (oyster,) of which 130 species are described. We have reason to think that the individuals have a natural life of at least six or seven years: but we have no reason to suppose that any one species has died out, since the Adamic creation. May we then, for the sake of an illustrative argument, take the duration of testacean species, one with another, at 1000 times the life of the individual? May we say, 6000 years?—We are dealing very liberally with our opponents. Yet, in examining the vertical evidences of the cessations of the fossil species, marks are found of an entire change in the forms of animal life; we find such cessations and changes to have occurred MANY times, in the thickness of but a few hundred feet of these slate-rocks. But the homogeneous, or nearly homogeneous deposit consists of many thousand feet; and it is only one of several, perhaps four, great formations which constitute this early system.

But when we rise to the Silurian formations, we find a long succession of strata, many thousand feet in thickness, and imbedding not fewer than 375 species belonging to the animal kingdom;—corallines, encrinites, analogues of crab and lobster, bivalve and univalve shells, and the skeletons and detached bones of fish.

The Old Red Sandstone, now called by a preferable name, the Devonian system, had been thought to be almost

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destitute of organic remains; but recent researches, particularly in Scotland, have brought to light numerous and highly interesting bones and skeletons of fishes: but none of them are such as belong to the present order of creation. They are all of species, and even genera, not now existing: and the same observation is to be made with respect to the fishes which occur more abundantly in a very thick and extensive formation which comes much later in the geological series, the New Red Sandstone, and especially that which is usually considered as one of its subordinate parts, the Magnesian Limestone.

Between these two great yet very distinct and distant Red Sandstone formations, there is, in many parts of Wales, England, and Scotland, the Mountain Limestone, usually 900 and more feet in thickness, and which consists of nothing else than the remains of coralline and testaceous animals compressed into masses of stone, hard and compact, often many miles in length and breadth. Over that, and in many of the same localities, we have the coalstrata, consisting entirely of compressed plants, with their sandstones, shales, and ironstones, full of land vegetables and presenting some fresh-water shells and fishes.

Above these, we are in the New Red just mentioned; 2000 feet of marl, clay, sand-rock, conglomerates, sulphate of lime, rock-salt, and magnesian lime-stone; red of all hues, white, and variegated: much less, in our country, replenished with the vestiges of living creatures, than the preceding or the succeeding formations; yet not destitute of them. In the equivalent rocks of Germany and France, organic remains are more frequent.

In one of the members of this formation, the first known appearance of reptile life presents itself, in several species of lizard-like animals. But in the beds which come next in the ascending order, the Lias, we are met by other and very different species, of the same family, of appalling

size, power, and armature, besides other orders; and through all the Oolitic strata, we find remains, in great variety and abundance; above fifty of plants; of the animal classes a number of species and forms of organization, which may well fill us with astonishment, from the zoophytes upwards, but as yet (so far as is known) only, as it were, just touching upon the mammifers. Neither, amidst the crowds of other animals, till we have risen over all the sandy, clayey, and chalk formations, do we find any further appearances of that class. The thousands of species, through whose periods we have thus in idea been passing, are all different from any in the now existing creation, though possessing generic and family analogies: and yet (with the remarkable and contested† exception just hinted at, the Stonesfield fossil, and see p. 82,) no mammiferous animals. When we have risen above the chalk, we discover in the shell-fish a small beginning of existing species; and, in the subsequent formations, the proportion increases till all the older species have successively become extinct, and the land, the fresh waters, and the ocean, come to be occupied by the present edition of creation. But many deposits and very long periods, from the chalk upwards,

* The reader should not fail, if he can, to inspect the specimens which are in the Long Gallery of the British Museum: the figures, by Mr. Hawkins, who collected the most of those specimens and chiseled them out of the rock; (see the note at page 96;) and the reduced figures in Dr. Buckland's Bridgewater Treatise, with his admirable enucleations of the structure and habits of the animals.

+ Some eminent anatomists are of opinion that the few bones in question (only two or three broken jaws, upon which the greatest men in this department have put forth their utmost powers of discrimination) belonged not to a mammal, but to a small reptile, of the lizard or iguana family, and to which those naturalists give the generic name of amphitherium. Sec. ed. Yet Mr. Owen's repeated examinations, in which his exquisite familiarity with Comparative Anatomy has been aided by microscopic observation of the interior structure of teeth, have confirmed the belief of Dr. Buckland and other distinguished men, that the animal was a small mammal, of a kind analogous to the opossum.