hatcher: diplodocus (maesh) 



61 



of an exceedingly luxuriant vegetation, in a moist tropical climate, lived Diplodocus 

 and numerous other huge members of the Sauropoda, as well as other Dinosaurs. 

 If we picture these or similar conditions as having prevailed over this region in 

 middle Mesozoic times we may form a very fair idea of the probable environments 

 attending the existence of these monsters. With the beginning of the Cretaceous 

 there began a subsidence over this region, and a great inland sea was formed which 

 gradually encroached upon the habitat of these animals, more and more restricting 

 the area adapted to them, so that at about the commencement of the Upper Cre- 

 taceous the entire region formerly occupied by them had become a shallow sea save 

 only certain islands of limited extent and perhaps otherwise poorly adapted as the 

 homes of such animals as were the Sauropoda. In this manner was accomplished 

 . the final extermination of this group of Dinosaurs, while the carnivorous Theropoda 

 and the herbivorous Predentata, through their greater ability to adapt themselves 

 to the changed environments, continued on throughout the entire Cretaceous and 

 have left their remains in great abundance imbedded in the sandstones and shales 

 of the Laramie, the closing period of Mesozoic times. 



Marsh, O. C. 



OSBORN, H. F. 



Holland, W. J. 

 Hatcher, J. B. 



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