258 LAKE SUPERIOR. 



and even in the chalk and tertiary beds. Thej existed in the same 

 wide range upon the continent of North America, and have been found 

 in Asia as well as in 'New Holland ; so that this family, now limited to 

 the continent of North America, and, if we include in it the Bichir 

 also, to two river basins of Africa, was once cosmopolite in its 

 geographical distribution. 



The natural consequence from such evidence is, that we cannot 

 arrive at a true insight into the relations of the animal creation, unless 

 we study, at the same time, the living animals, and those which have 

 become extinct ; and that a natural classification must associate the 

 fossils promiscuously in their natural relationship with the living 

 types. The separation of palaeontology from zoology, for the sake 

 of convenience in the study of geological phenomena, has been very 

 injurious to the real progress of zoology, and is so entirely unscientific, 

 that until they are again combined under the same head, even in our 

 elementary text books, we can hardly expect that zoology will make 

 the progress which extensive investigations carried on singly, in the 

 study of living and fossil animals, would lead us to expect. 



Moreover, the identification of fossils requires a close investiga- 

 tion of such characters as are shown in the only remains of extinct 

 species which have been preserved, and which are, almost exclusive- 

 ly, their solid parts. It is therefore very important that, in zoological 

 investigations, more attention should be paid to the characters derived 

 from such parts as are the only ones accessible in the study of fossils. 



The mutual advantages to be derived from such a course cannot but 

 be strikingly felt by those who have devoted their attention to the 

 study of fossils. It may even be said that the condition of fossil re- 

 mains, as they generally occur in rocks, has led naturalists to study 

 more carefully the living species, than they did before. I need only 

 mention the minuteness with which the skeletons of living animals 

 have been described since it has been necessary to identify extinct 

 species from isolated bones. 



The skeletons of fishes, which were neither correctly figured in 

 zoological drawings of these animals, nor minutely examined in their 

 structure, are no longer considered as unworthy of the attention of 

 minute observers. Even our knowledge of the structure of the 

 shells in rnollusca and of the wings of insects, has been improved with 



