560 HISTORY OF GEOLOGY. 



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. Konig, 

 Ichthyosaurus ; and Jts structure and constitution 

 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 . 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 Palaeontology ; and there is no branch 

 of human knowledge more fitted to stir men's 

 wonder, or to excite them to the widest physiolo- 

 gical 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 com- 

 parative anatomy. To show how extensive and 

 how conclusive is the science when thus directed, 

 we need only refer to Cuvier's Ossemens Fos- 



31 Geol. Trans, vol. v. 



