754 



HISTORICAL GEOLOGY. 



rN3. 



1180 



1180-1183. 



1181 



1182 a 



a tooth of which, from a skull described aiid figured by him. is represented 



half the natural size in Fig. 1180; the 

 1182 teeth were four inches long; also, 

 Pcdceoctonus Appalachiamis Cope, from 

 Phoenixville ; an anterior tooth having 

 a length of 3^ inches ; also Thecodon- 

 tosaurus gibbidens Cope, Palceosawus 

 Fraserianus Cope, Suchoprion aulacodus 

 Cope, from Phoenixville. 



CrocodiUcms. — The Crocodilians are 

 Thecodont species (that is, have the 

 teeth in sockets). They pertain to the 

 genus Belodon, and are characterized by 

 the Palaeic features of biconcave verte- 

 brae ; the jaws were long and slender, like 

 those of the Gavials. Teeth of two 

 species are represented in Figs. 1182, 

 1182 a, Belodon priscus of Leidy, and 

 Fig. 1183, B. Carolinensis of Cope, from 

 Pennsylvania and ISTorth Carolina. 



Bones of one species have been found by Marsh in the Connecticut sandstone. 



Goprolites are common in the shales at Phoenixville, Pa. 



5. Mammals. — The only Mammalian remains of the Atlantic border are two 

 jaw-bones, found in Chatham County, N. C, by E. Emmons. They belong to 



1184-1185. 



Dinosaurs. — Fig. 1180, Bathygnathus borealis; 



1181, Clepsysaiirus Pennsylvanicus. 

 Ceocodilians. — Fig. 1182, tooth of Belodon 



priscus ; 1182 a, section of same ; 1183, B. 



Carolinensis. Fig. 1180, Leidy; 1181-1183, 



E. Emmons. 



llS4a 



1185 a 



MAEsrpiAL Mammals. — Fig. 1184, Dromatherium sylvestre {x3); 1184 a, id. (x 1) ; 1185, Microconodon 



tenuirostris ( x 4) ; 1185 a, id. (x 1). Osborn. 



Insectivorous Marsupials, Dromatherium sylvestre of Emmons, and Microco- 

 nodon temdrostris of Osborn.* Mammals of similar character probably 

 spread over the continent, and may have been of many species. 



*Owen says of the Dromatherium that " this Triassic or Liassic Mammal would appear to 



