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Rh writers. The pioneers of the science in the 16th and 17th centuries put forth anticipations of some of the well-known modern principles, often followed by recantations, through deference to prevailing religious or traditional beliefs. There were the retarding influences of the Mosaic account of sudden creation, and the belief that fossils represented relics of a universal deluge. There were crude medieval notions that fossils were “freaks” or “sports” of nature (lusus naturae), or that they represented failures of a creative force within the earth (a notion of Greek and Arabic origin), or that larger and smaller fossils represented the remains of races of giants or of pygmies (the mythical idea).

As early as the middle of the 15th century Leonardo da Vinci (1452-1519) recognized in seashells as well as in the teeth of marine fishes proofs of ancient sea-levels on what are now the summits of the Apennines. Successive observers in Italy, notably Fracastoro (1483-1553), Fabio Colonna (1567-1640 or 1650) and Nicolaus Steno (1638-c. 1687), a Danish anatomist, professor in Padua, advanced the still embryonic science and set forth the principle of comparison of fossil with living forms. Near the end of the 17th century Martin Lister (1638-1712), examining the Mesozoic shell types of England, recognized the great similarity as well as the differences between these and modern species, and insisted on the need of close comparison of fossil and living shells, yet he clung to the old view that fossils were sports of nature. In Italy, where shells of the sub-Apennine formations were discovered in the extensive quarrying for the fortifications of cities, the close similarity between these Tertiary and the modern species soon led to the established recognition of their organic origin. In England Robert Hooke (1635-1703) held to the theory of extinction of fossil forms, and advanced the two most fertile ideas of deriving from fossils a chronology, or series of time intervals in the earth's history, and of primary changes of climate, to account for the former existence of tropical species in England.

The 18th century witnessed the development of these suggestions and the birth of many additional theories. Sir A. Geikie assigns high rank to Jean Étienne Guettard (1715-1786) for his treatises on fossils, although admitting that he had no clear idea of the sequence of formations. The theory of successive formations was soundly developing in the treatises of John Woodward (1665-1728) in England, of Antonio Vallisnieri (1661-1730) in Italy, and of Johann Gottlob Lehmann (d. 1767) in Germany, who distinguished between the primary, or unfossiliferous, and secondary or fossiliferous, formations. The beginnings of palaeogeography followed those of palaeometeorology. The Italian geologist Soldani distinguished (1758) between the fossil fauna of the deep sea and of the shore-lines. In the same year Johann Gesner (1709-1790) set forth the theory of a great period of time, which he estimated at 80,000 years, for the elevation of the shell-bearing levels of the Apennines to their present height above the sea. The brilliant French naturalist Georges Louis Leclerc, comte de Buffon (1707-1788), in Les Époques de la nature, included in his vast speculations the theory of alternate submergence and emergence of the continents. Abraham Gottlob Werner (1750-1817), the famous exponent of the aqueous theory of earth formation, observed in successive geological formations the gradual approach to the forms of existing species.

Invertebrate palaeontology founded by Lamarck, vertebrate ''palaeontology by Cuvier. Palaeontology connected with comparative'' ''anatomy by Cuvier. Invertebrate fossils employed for the'' definite division of all the great periods of time.—Although pre-evolutionary, this was the heroic period of the science, extending from the close of the 18th century to the publication of Darwin's Origin of Species in 1859. Among the pioneers of this period were the vertebrate zoologists and comparative anatomists Peter Simon Pallas, Pieter Camper and Johann Friedrich Blumenbach. Pallas (1741-1811) in his great journey (1768-1774) through Siberia discovered the vast deposits of extinct mammoths and rhinoceroses. Camper (1722-1789) contrasted (1777) the

Pleistocene and recent species of elephants and Blumenbach (1752-1840) separated (1780) the mammoth from the existing species as Elephas primigenius. In 1793 Thomas Pennant (1726-1798) distinguished the American mastodon as Elephas americanus.

Political troubles and the dominating influence of Werner's speculations checked palaeontology in Germany, while under the leadership of Lamarck and Cuvier France came to the fore. J. B. Lamarck (1744-1829) was the founder of invertebrate palaeontology. The treatise which laid the foundation for all subsequent invertebrate palaeontology was his memoir, Sur ''les fossiles des environs de Paris. . .'' (1802-1806). Beginning in 1793 he boldly advocated evolution, and further elaborated five great principles—namely, the method of comparison of extinct and existing forms, the broad sequence of formations and succession of epochs, the correlation of geological horizons by means of fossils, the climatic or environmental changes as influencing the development of species, the inheritance of the bodily modifications caused by change of habit and habitat. As a natural philosopher he radically opposed Cuvier and was distinctly a precursor of uniformitarianism, advocating the hypothesis of slow changes and variations, both in living forms and in their environment. His speculations on phylogeny, or the descent of invertebrates and vertebrates, were, however, most fantastic and bore no relation to palaeontological evidence.

It is most interesting to note that William Smith (1769-1839), now known as the “father of historical geology,” was born in the same year as Cuvier. Observing for himself (1794-1800) the stratigraphic value of fossils, he began to distinguish the great Mesozoic formations of England (1801). Cuvier (1769-1832) is famous as the founder of vertebrate palaeontology, and with Alexandre Brongniart (1770-1847) as the author of the first exact contribution to stratigraphic geology. Early trained as a comparative anatomist, the discovery of Upper Eocene mammals in the gypsum quarries of Montmartre found him fully prepared (1798), and in 1812 appeared his Recherches sur les ossemeus fossiles, brilliantly written and constituting the foundation of the modern study of the extinct vertebrates. Invulnerable in exact anatomical description and comparison, he failed in all his philosophical generalizations, even in those strictly within the domain of anatomy. His famous “law of correlation,” which by its apparent brilliancy added enormously to his prestige, is not supported by modern philosophical anatomy, and his services to stratigraphy were diminished by his generalizations as to a succession of sudden extinctions and renovations of life. His joint memoirs with Brongniart, Essai sur la geographie mineralogique des environs de Paris avec une carte géognostique et des coupes de terrain (1808) and Description géologique des environs de Paris (1835) were based on the wonderful succession of Tertiary faunas in the rocks of the Paris basin. In Cuvier's defence Charles Depéret maintains that the extreme theory of successive extinctions followed by a succession of creations is attributable to Cuvier's followers rather than to the master himself. Depéret points also that we owe to Cuvier the first clear expression of the idea of the increasing organic perfection of all forms of life from the lower to the higher horizons, and that, while he believed that extinctions were due to sudden revolutions on the surface of the earth, he also set forth the pregnant ideas that the renewals of animal life were by migration from other regions unknown, and that these migrations were favoured by alternate elevations and depressions which formed various land routes between great continents and islands. Thus Cuvier, following Buffon, clearly anticipated the modern doctrine of faunal migrations. His reactionary and retarding ideas as a special creationist and his advocacy of the cataclysmic theory of change exerted a baneful influence until overthrown by the uniformitarianism of James Hutton (1726-1797) and Charles Lyell (1797-1875) and the evolutionism of Darwin.

The chief contributions of Cuvier's great philosophical opponent, Étienne Geoffrey St Hilaire (1772-1844), are to be found in his maintenance with Lamarck of the doctrine of the mutability of species. In this connexion he developed his