in their seas; but the German and English writers, as Gesner,21 Raspe,22 and Brander,23 had perceived that the fossil-shells were either of unknown species, or of such as lived in distant latitudes. To decide that the animals and plants, of which we find the remains in a fossil state, were of species now extinct, obviously required an exact and extensive knowledge of natural history. And if this were so, to assign the relations of the past to the existing tribes of beings, and the peculiarities of their vital processes and habits, were tasks which could not be performed without the most consummate physiological skill and talent. Such tasks, however, have been the familiar employments of geologists, and naturalists incited and appealed to by geologists, ever since Cuvier published his examination of the fossil inhabitants of the Paris basin. Without attempting a history of such labours, I may notice a few circumstances connected with them. Sect. 4.-Advances in Palæontology.-Cuvier. So long as the organic fossils which were found in the strata of the earth were the remains of marine animals, it was very difficult for geologists to be assured that the animals were such as did not exist in any part or clime of the existing ocean. But when large land and river animals were discovered, different from any known species, the persuasion that they were of extinct races was forced upon the naturalist. Yet this opinion was not taken up slightly, nor acquiesced in without many struggles. Bones supposed to belong to fossil elephants, were some of the first with regard to which this conclusion was established. Such remains occur in vast numbers in the soil and gravel of almost every part of the world; especially in Siberia, where they are called the bones of the mammoth. They had been noticed by the ancients, as we learn from Pliny;24 and had been ascribed to human giants, to elephants imported by 21 Lyell, i. 70. 22 Ib. 74. 23 Ib. 76. the Romans, and to many other origins. But in 1796, Cuvier had examined these opinions with a more profound knowledge than his predecessors; and he thus stated the result of his researches.25 'With regard to what have been called the fossil remains of elephants, from Tentzelius to Pallas, I believe that I am in a condition to prove, that they belong to animals which were very clearly different in species from our existing elephants, although they resembled them sufficiently to be considered as belonging to the same genera.' He had founded this conclusion principally on the structure of the teeth, which he found to differ in the Asiatic and African elephant; while, in the fossil animal, it was different from both. But he also reasoned in part on the form of the skull, of which the best-known example had been described in the Philosophical Transactions as early as 1737.20 'As soon,' says Cuvier, at a later period, as I became acquainted with Messerschmidt's drawing, and joined to the differences which it presented, those which I had myself observed in the inferior jaw and the molar teeth, I no longer doubted that the fossil elephants were of a species different from the Indian elephant. This idea, which I announced to the Institute in the month of January, 1796, opened to me views entirely new respecting the theory of the earth; and determined me to devote myself to the long researches and to the assiduous labours which have now occupied me for twenty-five years. 26 We have here, then, the starting-point of those researches concerning extinct animals, which, ever since that time, have attracted so large a share of notice from geologists and from the world. Cuvier could hardly have anticipated the vast storehouse of materials which lay under his feet, ready to supply him occupation of the most intense interest in the career on which he had thus entered. The examination of the strata Mém. Inst. Math. et Phys. serschmidt in 1722. Phil. Trans. tom. ii. p. 4. xl. 446. 26 Described by Breyne from a specimen found in Siberia by Mes 27 Ossemens Fossiles, second edit. i. 178. on which Paris stands, and of which its building consist, supplied him with animals, not only different from existing ones, but some of them of great size and curious peculiarities. A careful examination of the remains which these strata contain was undertaken soon after the period we have referred to. In 1802, Defrance had collected several hundreds of unde scribed species of shells; and Lamarck 28 began a series of Memoirs upon them; remodelling the whole of Conchology, in order that they might be included in its classifications. And two years afterwards (1804) appears the first of Cuvier's grand series of Memoirs containing the restoration of the vertebrate animals of these strata. In this vast natural museum, and in contributions from other parts of the globe, he discovered the most extraordinary creatures: the Palæotherium, which is intermediate between the horse and the pig; the Anoplotherium, which stands nearest to the rhinoceros and the tapir; the Megalonix and Megatherium, animals of the sloth tribe, but of the size of the ox and the rhinoceros. The Memoirs which contained these and many other discoveries, set the naturalists to work in every part of Europe. Another very curious class of animals was brought to light principally by the geologists of England; animals of which the bones, found in the lias stratum, were at first supposed to be those of crocodiles. But in 1816,30 Sir Everard Home says, 'In truth, on a consideration of this skeleton, we cannot but be inclined to believe, that among the animals destroyed by the catastrophes of remote antiquity, there had been some at least that differ so entirely in their structure from any which now exist as to make it impossible to arrange their fossil remains with any known class of animals.' The animal thus referred to, being clearly intermediate between fishes and lizards, was named by Mr. König, Ichthyosaurus; and its structure and con 28 Annales du Muséum d'Hist. Nat. tom. i. p. 308, and the following volumes. 29 Daubuisson, ii. 411. 30 Phil. Trans. 1816, p. 20. stitution were more precisely determined by Mr. Conybeare in 1821, when he had occasion to compare with it another extinct animal of which he and Mr. de la Beche had collected the remains. This animal, still more nearly approaching the lizard tribe, was by Mr. Conybeare called Plesiosaurus.31 Of each of these two genera several species were afterwards found. Before this time, the differences of the races of animals and plants belonging to the past and the present periods of the earth's history, had become a leading subject of speculation among geological naturalists. The science produced by this study of the natural history of former states of the earth has been termed Paleontology; and there is no branch of human knowledge more fitted to stir men's wonder, or to excite them to the widest physiological speculations. But in the present part of our history this science requires our notice, only so far as it aims at the restoration of the types of ancient animals, on clear and undoubted principles of comparative anatomy. To show how extensive and how conclusive is the science when thus directed, we need only refer to Cuvier's Ossemens Fossiles,32 a work of vast labour and profound knowledge, which has opened wide the doors of this part of geology. I do not here attempt even to mention the labours of the many other eminent contributors to Paleontology; as Brocchi, Des Hayes, Sowerby, Goldfuss, Agassiz, who have employed themselves on animals, and Schlottheim, Brongniart, Hutton, Lindley, on plants. [2nd Ed.] [Among the many valuable contributions to Paleontology in more recent times, I may especially mention Mr. Owen's Reports on British Fossil Reptiles, on British Fossil Mammalia, and on the Extinct Animals of Australia, with descriptions of certain Fossils indicative of large Marsupial Pachydermata: and M. Agassiz's Report on the Fossil Fishes of the Devonian 31 Geol. Trans. vol. v. 22 The first edition appeared in 1812, consisting principally of the Memoirs to which reference has already been made. System, his Synoptical Table of British Fossil Fishes, and his Report on the Fishes of the London Clay. All these are contained in the volumes produced by the British Association from 1839 to 1845. A new and most important instrument of palæontological investigation has been put in the geologist's hand by Prof. Owen's discovery, that the internal structure of teeth, as disclosed by the microscope, is a means of determining the kind of the animal. He has carried into every part of the animal kingdom an examination founded upon this discovery, and has published the results of this in his Odontography. As an example of the application of this character of animals, I may mention that a tooth brought from Riga by Sir R. Murchison was in this way ascertained by Mr. Owen to belong to a fish of the genus Dendrodus. (Geology of Russia, i. 67.)] When it had thus been established, that the strata of the earth are characterized by innumerable remains of the organized beings which formerly inhabited it, and that anatomical and physiological considerations must be carefully and skilfully applied in order rightly to interpret these characters, the geologist and the palæontologist obviously had, brought before them, many very wide and striking questions. Of these we may give some instances; but, in the first place, we may add a few words concerning those eminent philosophers to whom the science owed the basis on which succeeding speculations were to be built. Sect. 5.-Intellectual Characters of the Founders of Systematic Descriptive Geology. It would be in accordance with the course we have pursued in treating of other subjects, that we should attempt to point out, in the founders of the science now under consideration, those intellectual qualities and habits to which we ascribe their success. The very recent date of the generalizations of geology, which has hardly allowed us time to distinguish the calm expression of the opinion of the wisest judges, might, in this |