Cc if 2 2. 
U. S. GEOLOGICAL SURVEY BULLETIN 707 SHEET No. 3 
3g 106 30° si Sheet No. + COLORADO 105 30 
GEOLOGIC AND TOPOGRAPHIC MAP Approximately Ser nk ' 
OF THE Ponsa ee ep 
0 5 10 15 Kilometers 
RIO GRANDE ROUTE ee 3 
From Denver, Colorado, to Salt Lake City, Utah "Tas eens te aa terete oe oaae tame ee 
Compiled from United States Geological Survey atlas 
sheets and reports, from railroad alinements and pro- 
files supplied by the Denver & Rio Grande Western 
Rellet shading by R. W. Berry 
PREPARED UNDER THE DIRECTION OF 
GEORGE OTIS SMITH, DIRECTOR 
DAVID WHITE, Chief Geologist C. H. BIRDSEYE, Chief Topographic Engineer 
M. R. CAMPBELL, Geologist A. C. ROBERTS, Topographer 
1922 
EXPLANATION 
Age Thickness 
in feet 
Mountain glaciers as they were during the Great Ice Age Pleistocene 
eet i oe cer a 
Dark marine shale (Mancos shale) 2,500-+ 
i Upper Cretaceous 
Brown sandstone (Dakota sandstone) } 50 
Variegated shale and sandstone (Gunnison formation) Gretnenons = and = 490+ Be 
: 6S 
Red sandstone and shale (Maroon formation) 1,500 ia] = 
. Carboniferous ‘At 
: | (Pennsylvanian) >. 
Red sandstone, conglomerate, and shale (Weber formation) J 2,300 “4 & 
if ; 
Blue limestone (Leadville limestone, Ouray limestone) Cael) 200 
ra : j : and Devonian 
{ Parting quartzite 40 PISS 
Limestone and | White limestone 160’ Fan 375 
btsilorueagt es (Poe quartzite (Sawatch 
quartzite) 175’ 
Granite Pre-Cambrian 
Lava flows | , 
\ Tertiary 
Intrusives J 
