THE CRETACEOUS PERIOD. 



155 



above. The break between the Laramie and Eocene is locally a great 

 one, — has even been regarded as one of the greatest breaks recorded 

 in the strata of the continent. 1 Locally, however, the association 



374 



Fig. 398. — Map of a small area in Colorado, showing the outcrops of faulted Cre- 

 taceous formations. Kd, Dakota; Kys (Graneros shale), Kgn (Greenhorn lime- 

 stone), Kcr (Carlisle shale), Kt (Timpas shale), and Ka (Apishapa shale), Colorado 

 series; Kp (Pierre shale), Montana series; Tri, igneous rocks of Tertiary age 

 (Hills. Walsenburg, Colo., folio, U. S. Geol. Surv.) 



of the Laramie and Eocene is so intimate that agreement concern- 

 ing the reference of certain beds, and even thick formations, has not 

 been reached. Within what has often been called the Laramie series, 

 there are local unconformities. Where these are slight, they prob- 

 ably have little significance in determining the classification of the 

 beds. Slight unconformities are common in the Pennsylvania!! system 

 of the east, with which this series is most nearly allied in genesis. But 



1 Emmons, Orographic movements of the Rockv Mountains. Bull. G. S, A., 

 Vol. I, p. 285. 



