MOOK, STUDY OF THE MORRISON FORMATION 131 



Vertebeate Fauna of the Moerison FoKMATioisr 



The vertebrate fauna of the Morrison formation is a remarkable one. 

 It consists of a number of primitive mammals, a variety of reptiles, and 

 a few fish. The most conspicuous element in the fauna is the dinosaurs. 

 Eepresentatives of the three principal groups of dinosaurs are present, 

 each with a number of forms. The Sauropoda are especially abundant, 

 being represented by many genera and species. In fact, all the American 

 Sauropoda occur in beds of Morrison age, or very close to it. It is be- 

 yond the province of the present paper to enter into an extensive dis- 

 cussion of the various vertebrate remains in detail. The more important 

 forms are discussed briefly. Eeferences are given to the original litera- 

 ture on the various forms. 



MAMMALIA 



AUodon laticeps Marsh 



Allodon laticeps Marsh, Notice of 'New Jurassic Mammals. Amer. 

 Journ. Sci., 3rd ser., vol. xxi, p. 511, 1881. 



Allodon fortis Marsh 



Allodon fortis Marsh, American Jurassic Mammals. Amer. Journ. 

 Sci., 3rd ser., vol. xxxiii, p. 327 (331), 1887. 



Asthenodon segnis Marsh 



Asthenodon segnis Marsh, American Jurassic Mammals. Amer. Journ. 

 Sci., 3rd ser., vol. xxxi, p. 327 (336), 1887. 



» Dryolestes priscus Marsh 



Dryolestes priscus Marsh, Fossil Mammals from the Jurassic of the 

 Rocky Mountains. Amer. Journ. Sci., 3rd ser., vol. xv, p. 459, 1878. 



Dryolestes arcuatus 



Dryolestes arcuattis Marsh, Notice of New Jurassic Mammals. Amer. 

 Journ. Sci., 3rd ser., vol. xviii, p. 396 (397), 1879. 



Dryolestes gracilis Marsh 



Dryolestes gracilis Marsh, Notice of New Jurassic Mammals. Amer. 

 Journ. Sci., 3rd ser., vol. xxi, p. 511 (513), 1881. 



