508 



GEOLOGY OF THE DENVER BASIN. 



In the Wyoming Basin, west of the mountains, the same species are 

 abundant, and with them have been found remains of a very remarkable 

 reptile (Macelognathus), figs. 65 and 66, and also a pterodactyl (Dermo- 

 dactylus montanus). A batrachian (Eolatrachus agilis) and a peculiar fish 

 (Ceratodus giintheri), fig. 67, have likewise been found in this horizon. A 

 single bird (Laopteryx pri&ciis), discovered near Como, Wyo., has also been 

 described by the writer. All these species are probably represented in the 



Fig. 68. —Left lower jaw of Stylatodon gracilis Marsh; outer view. 

 Fig. 69. — Right lower jaw of Diplocynodon i icior Marsh; outer view. 

 Fig. 70.— Left lower jaw of Otenaeodon serrate* Marsh : inner view. 

 a, canine; &, condyle ;* c, ooronoid process; d, angle. 



times natural size, 

 ice natural size. 

 ■ times natural size. 



Denver region, and may be brought to light at any time. Many other 

 tonus of much scientific interest, but known only from fragmentary 

 remains, have been found in this horizon. 



JURASSIC MAMMALS. 



The most important of the remaining vertebrate fossils from the 

 Atlantosaurus h^U are the diminutive mammals, of which a few only have 



