388 ZOOLOGY. 



teeth." Twenty-one species of the new family are recognized, 12 of 

 which are confined to the American Lower Miocene and 1 to the Ameri- 

 can Uiiper Miocene. Of the other species in Europe 3 occur in the 

 Upper Eocene, 2 in the Lower Miocene, 1 in the Upper Miocene, and in 

 India 1 in the later Miocene or Pliocene. 



THE REPRESENTATIVE STRATA OF EUROPE AND NORTH AMERICA AS 

 DETERMINED FROM VERTEBRATE DATA.* 



There has been only approximate parallelism of the strata of North 

 America and Europe from their Invertebrate remains, and inasmuch as 

 the later deposits are better characterized by the Vertebrates than by 

 the Invertebrates, a comparison with relation to the former was much 

 needed, and this Professor Cope has lately undertaken. He premises 

 that " if the types of life have originated independently we will find evi 

 dence of it by studying American palaeontology ; if their origin has 

 been through gradual modification, America should furnish us with 

 many intermediate faunae." To solve this question he thinks "the 

 identification of the generic types of i^orth American Vertebrata has now 

 advanced to a point which renders such a comparison possible." This 

 comparison is begun with the coal measures and especially with the 

 Batrachiaus of that i)eriod. The Carboniferous Batrachians are " not 

 yet sufficiently well known to enable the most exact comparison to be 

 made, but close parallels, if not identities, of genera exist. Such are 

 the Oestocephalus and Ceraterpeton^ of Ohio, as compared with the 

 Urocordylus and Ceraterpeton of Great Britain." The Permian vertebrate 

 fauna, as represented in Illinois and Texas, " exhibits close parallels, but 

 not yet generic identity in the two continents." The Triassic fauna is 

 much better known in Europe than in America, the marine Trias being 

 little developed, and the vertebrate fauna of the Muschelkalk being en- 

 tirely unknown in the latter country. The Keuper, however, is repre- 

 sented, and a characteristic type (Belodon) existed in both continents. 

 The Jurassic fauuae have been thought to be but poorly represented in 

 the New World, " We do not yet know any deposits in North America 

 which contain the typical reptilian genera Plesiosaiirus^ Ichthyosaurus, 

 Pliosaurus, and Dimorpliodon, or the fishes of the Dapediidce; " although 

 recent discoveries by Professor Marsh presage much for the future. "A 

 few more characteristic fossils of the Eocky Mountain region represent 

 the Oolite — particularly the upper Oolite — while Teleosaurus and Steneo- 

 saurus, and their allies, are not yet known from North American beds." 



The Cretaceous fauna is very well developed in North America. " The 

 ocean of the interior of the continent deepened from the beginning of 

 the period until the epoch of the Niobrara, and then gradually shallowed 

 until the elevations of the bottom began to divide the waters. The clos- 

 ing scenes of this great epoch were enacted amid a labyrinth of lagoons 



*Cope (E. D. ). The Relations of the Horizons of Extinct Vertebrata of Europe and 

 North America. Bui. U. S. Geol. and Geog. Survey Ter., vol. v, pp. 33-54. 



