368 LOUIS AGASSTZ. 



collection from the Old Red of Russia, and 

 various other specimens from the same local- 

 ity. Not only on account of their peculiar 

 structure were the fishes of the Old Red in- 

 teresting to Agassiz, but also because, with 

 this fauna, the vertebrate type took its place 

 for the first time in what were then supposed 

 to be the most ancient fossiliferous beds. 

 When Agassiz first began his researches on 

 fossil fishes, no vertebrate form had been dis- 

 covered below the coal. The occurrence of 

 fishes in the Devonian and Silurian beds 

 threw the vertebrate type back, as he believed, 

 into line with all the invertebrate classes, and 

 seemed to him to show that the four great 

 types of the animal kingdom, Radiates, Mol- 

 lusks, Articulates, and Vertebrates, had ap- 

 peared together.^ "It is henceforth demon- 

 strated," says Agassiz, "that the fishes were 

 included in the plan of the first organic com- 

 binations which made the point of departure 

 for all the living inhabitants of our globe in 

 the series of time." 



In his opinion this simultaneity of appear- 

 ance, as well as the richness and variety dis- 

 played by invertebrate classes from the begin- 



1 Introduction to the Poissons Fossiles du Vieux Gres Rougey 

 p. 22. 



