678 



INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



development of the Cretaceous is more like tKat of the Rock Springs dome and other 

 areas farther north, though the upper beds are largely concealed by overlap of the 

 Wind River Eocene. Woodruff®*^ has described the part of the basin that is 

 included within the Lander oil field and gives the following tabular description of the 

 Cenozoic and Mesozoic formations : 



Geologic formations [Cenozoic and Mesozoic] in the Lander oilfield. 



K 13. NOBTHERN COLOBADO AND WYOMING. 



In northwestern Colorado Cretaceous strata outcrop between the pre-Cambrian 

 of the Park Range and the Tertiary of the wide basin on the west. Just north of 

 the fortieth parallel is the Yampa coal field, which has been examined by Fenne- 

 man and Gale.^^® They give the following section: 



