lo THE COLLECTION OF FOSSIL VERTEBRATES 



East Wing. Hall No. 407. Fossil Reptiles, Amphibians and 

 Fishes. 



In addition 



East Corridor, No. 405 (in which are the elevator and stair- 

 ways), contains fossil Marine Reptiles and Fishes of the Age of 

 Reptiles. 



SKELETON OF THE GREAT MARINE LIZARD IN THE EAST CORRIDDR 



THE EAST CORRIDOR. No. 405. 



On stepping from the elevator the visitor sees before him a 

 case filled with skulls and skeletons of the marine reptiles and 

 The Preset- ^shes which inhabited the great inland sea that once 

 vation of spread over the center of the North American conti- 

 Fossils in nent, from Canada to Mexico, The reptiles were of 

 ■ kinds now long extinct, Plesiosaurs with long snaky 

 neck, short bulky body with long flippers and stubby tail, and 

 Mosasaurs with short neck and longer tail. Some of the fishes 

 were ancestors, collateral or direct, of certain modern fishes, 

 others belonged to groups now extinct. These animals lived and 

 died, their carcasses sank to the bottom of the sea, and were 

 buried in whatever sediment was being deposited there — soft 

 white ooze in the open sea, dark gray or black mud nearer the 

 shores. In the course of ages this ooze or mud settled gradually 

 and consohdated into chalk or shale. Afterwards as the conti- 

 nent rose above the waters and assumed more nearly its present 

 dimensions, the rivers flowing over the broad plains excavated 



