BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 26, pp. 323-334 AUGUST 17, 1915 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



SATJEOPODA AND STEGOSAUEIA OF THE MORRISON OF 



NORTH AMERICA COMPARED WITH THOSE OF 



EUROPE AND EASTERN AFRICA ^ 



BY KICHARD SWANN LULL 



{Read before the Paleontological Society December 30, 101 J^) 



CONTENTS 



Page 



Introductory >, 323 



Sauropoda . . . ., 324 



Stegosauria 325 



Migratory roads 326 



Geographic and geologic distribution .326 



Sauropoda 326 



Stegosauria 327 



Three vistas of dinosaurian societies .327 



Tendaguru district of German East Africa 328 



General description 328 



Sauropoda .328 



Predentata 329 



Wealden .330 



Sauropoda .3.30 



Stegosauriji .332 



Moi-rison ,332 



Summary 333 



Introductory 



In discussing dinosaurs from a stratigraphic point of view, only those 

 groups are of value which are of a relatively high degree of specialization 

 and whose evolutionary stages are so sharply marked that a comparison 

 of those remotely removed geographically can be made with some degree 

 of accuracy. On this account the conservative carnivorous forms, whose 

 chief evolutionary change is increase of stature, are of little value. The 



1 Contrilmtion to the symposium held at the Philadelphia meeting December 30. 1014. 

 Manuwciipt received by the Secretary of the Society April 'A, 1915. 



(323) 



