BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 25, pp. 341-354 September 15, 1914 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



BOUNDARY BETWEEN CRETACEOUS AND TERTIARY IN 

 NORTH AMERICA AS INDICATED BY STRATIGRAPHY 

 AND INVERTEBRATE FAUNAS^ 



BY TIMOTHY W. STANTON 



{Presented before the Paleontological Society December 31, 1918) - 



CONTENTS 



Page 



Typical Cretaceous and Eocene of western Europe 341 



Contact between marine Cretaceous and marine Eocene in North America . 342 

 Variations in Upper Cretaceous sedimentation of the Interior Province. .. 343 



General discussion .... 343 



Evidence of land areas in the Rocky Mountain region 344 



Evolution of unconformities 347 



The Lance formation 848 



Distribution and general character 848 



Development in North and South Dakota 349 



Review of investigations... 349 



Lower member and its relations with the Fox Hills 850 



Marine member and its Cretaceous fauna 351 



Conclusion 853 



Typical Cretaceous and Eocene of western Europe 



It should be remembered at the outset that the Cretaceous system was 

 first described in England, and that the Anglo-Parisian basin can per- 

 haps with justice be considered the typical area of both Cretaceous and 

 Eocene. Among English geologists there has been some difference of 

 opinion concerning the real character of the boundary between Cretaceous 

 and Eocene, but the statement by Geikie in his text-book may be ac- 

 cepted as conservative. He says : "In England the interval between the 

 Cretaceous and the next geological period represented there by sedi- 

 mentary formations is marked by the abrupt line which separates the 

 chalk from all later accumulations, and by the evidence that the chalk 

 seems to have been in some places extensively denuded before even the 

 oldest of what are called the Tertiary formations were deposited upon the 



1 Manuscript received by the Secretary of tlie Geological Society June 14, 1914. 

 Contribution to the symposium held at the Princeton meeting December 31, 1913, 

 and January 1, 1914. 



Published by permission of the Director of the U. S. Geological Survey. 



(341) 



