220 A CENTUEY OF SCIENCE 



such assemblage to the most modern, an idea of the most 

 fundamental importance and one with which he is rarely 

 credited. He believed in the sudden and complete 

 extinction of faunas, and the facts then known were in 

 accord with this idea, as no common genera nor transi- 

 tional forms connected the creatures of the Paris gypsum 

 with the mastodons, elephants, and hippopotami which 

 the later strata disclosed. It is n'ot remarkable, there- 

 fore, that Cuvier advanced his theory of catastrophism to 

 account for these extinctions. He should not, however, 

 according to Deperet, be credited with the idea of suc- 

 cessive re-creations, such as that held by D'Orbigny and 

 others, but of repopulation by immigration from some 

 area which the catastrophe, be it flood or other destruc- 

 tive agency, failed to reach. 



Cuvier was followed in Europe by a number of illus- 

 trious men, none of whom, however, with the exception of 

 Sir Eichard Owen, possessed his breadth of knowledge 

 of comparative anatomy upon which to base their 

 researches among the prehistoric. The more notable of 

 them may be enumerated before going on to a discussion 

 of the American contributions to the science. 



They were, first, Louis Agassiz, a pupil of Cuvier and 

 later a resident of America, whose researches on the fos- 

 sil fishes of Europe are a monumental work, the result of 

 ten years of investigation in all of the larger museums of 

 that continent, and which appeared in 1833-43, while he 

 was yet a young man. The fishes were practically the 

 only fossil vertebrates to come within the scope of his 

 investigations, for his later time was Consumed in the 

 study of glaciers and of recent marine zoology. Another 

 student of these most primitive vertebrates who left 

 an enduring monument was Johannes Miiller. Huxley, 

 Traquair, and Jaekel also did masterly work upon this 

 group, while Smith Woodward of the British Museum is 

 considered the highest living authority upon fossil fishes. 



Of the Amphibia, the most famous foreign students 

 were Brongniart, Jaeger, Burmeister, Von Meyer, and 

 Owen, although Owen's claim to eminence lies rather in 

 the investigations of fossil reptiles which he began in 

 1839 and continued over a period of fifty years of 

 remarkable achievement. Not only did he describe the 



