CHAPTER V

CREATURES OF THE PAST

     Beginning Palaeontological Work—­Fossil Amphibia and
     Reptilia—­Ancestry of Birds—­Ancestry of the Horse—­Imperfect
     European Series Completed by Marsh’s American Fossils—­Meaning of
     Geological Contemporaneity—­Uniformitarianism and Catastrophism
     Compared with Evolution in Geology—­Age of the
     Earth—­Intermediate and Linear Types.

Although Huxley took a post connected with Geology only because it was the most convenient opening for him, it was not long before he became deeply interested not only in the fossils, which at first he despised, but in the general problems of geology.  He began by co-operation with Mr. Salter in the determination of fossils for the Geological Survey.  The mere work of defining genera and species and naming and describing new species appealed very little to him.  He had none of the collector’s passion for new species; his interest in a creature being not whether or no it was new to science, but what general problems of biology its structure helped to elucidate.  While he assisted in the routine work of determining the zooelogical position of the fossils sent in to the museum by the Survey, he carried investigations much farther than the duties of the post required when interesting zooelogical problems arose.  His earliest notes were written in association with his colleague, and consisted of technical descriptions of some small fossils from the Downton Sandstones which were supposed to be fish-shields.  The peculiarities of structure presented by these aroused his interest, and he began an elaborate series of investigations upon palaeozoic fishes in general.  Earlier zooelogists, such as the great Agassiz, had devoted most of their attention to careful and exact description of the different fossil fishes with which they became acquainted.  Huxley at once began to investigate the relations that existed among the different kinds of structure exhibited in the different fish.  He laid down the lines upon which future work has been conducted, and, precisely as he did in the case of molluscs, he started future investigators upon lines of research the ends of which have not yet been reached.  His work upon Devonian Fishes, published in 1861, threw an entirely new light upon the affinities of these creatures, and still remains a standard work.

He made a similar, although less important, series of investigations upon some of the great extinct Crustacea; but, perhaps, his most important palaeontological work was done later, after he had been convinced by Darwin of the fact of evolution.  In 1855 he had expressed the opinion that the study of fossils was hopeless if one sought in it confirmation of the doctrine of evolution; but five-and-twenty years’ continuous work completely reversed his opinion, and in 1881, addressing the British Association at York he declared