BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 25, pp. 325-340 SEPTEMBER 15, 1914 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



CRETACEOUS-TEETIARY BOUNDARY IN THE ROCKY 

 MOUiNTTAIN REGION ^ 



BY F. H. KNOWLTON" 



(Presented before the Paleontological Society December SI, 1913) 



CONTENTS 



Page 



Introduction. 325 



Stratigraphic evidence 325 



Paleobotanical evidence 331 



DiastropMc evidence 334 



The European time scale 335 



Vertebrate evidence 337 



Invertebrate evidence 339 



Conclusions 340 



Introduction 



The thesis of this paper is as follows : It is proposed to. show that the 

 dinosaur-bearing beds known as "Ceratops beds," '^^Lance Creek beds," 

 Lance formation, "Hell Creek beds," "Somber beds," "Lower Port 

 LTnion," Laramie of many writers, "Upper Laramie," Arapahoe, Denver, 

 Dawson, and their equivalents, are above a major unconformity and are 

 Tertiary rather than Cretaceous in age. 



As this is essentially a stratigraphic problem and not, as some assume, 

 an exclusively paleontologic one, a certain amount of structural data are 

 necessary as a setting for the paleontology. It is proposed, therefore, 

 first, briefly to present the evidence on which this unconformity is predi- 

 cated. 



Stratigraphic Evidence 



The geological formations here involved are spread widely over the 

 States of New Mexico, Colorado, Wyoming, the Dakotas, Montana, and 



1 Manuscript received by the Se<;retary of the Geological Society June 14, 1914. 

 Contribution to the symposium held at the Princeton meeting of the Society Decem- 

 ber 31, 1913, and January 1, 1914. 



Published with the permission of the Director of the IT. S. Geological Survey. 



(325) 



