402 W. D. MATTHEW THE CRETACEOUS-TERTIARY PROBLEM 



the definition, it is very improbable that the Laramie was coextensive 

 with the original limits of the older Cretaceous formations. Between the 

 Niobrara and Laramie there was a widespread and considerable uplift on 

 the plains, probably much intensified along the mountain ridges, and the 

 erosion due to the latter probably supplied the materials for the Laramie 

 sedimentation, as their further uplift did for the subsequent continental 

 formations of that region. 



