U. S. GEOLOGICAL SURVEY 



BULLETIN 707 SHEET No. 



GEOLOGIC AND TOPOGRAPHIC MAP 



OF THE 



RIO GRANDE ROUTE 



From Denver, Colorado, to Salt Lake City, Utah 



Compiled from United States Geological Survey atlas 

 sheets and reports, from railroad alinements and pro- 

 files supplied by the Denver & Rio Grande Western 

 Railroad Co., and from additional information col- 

 lected with the assistance of that company 



PREPARED UNDER THE DIRECTION OF 

 GEORGE OTIS SMITH, DIRECTOR 



1922 

 EXPLANATION 



Age Tbicknesa 



A Mountain glaciers as they 



8 Gravel, sand, and clay 



J Dark marine shale iMancos sbale^ 



M Brown sandstone (Dakota sandBtone) 



N Variegated shale and aandatone (Gannieon formation 



R Red sandstone and shale (Maroon formation) 



during the Great Ice Age Pleistocene 



Upper Cretaceous 



S Red sandstone, conglom 



', and ahale (Weber formation) 



Cretaceous (?) and 400+ 

 Jurassic 



1.500 



Pre-Cambrian 



