PLEISTOCENE HISTORY OF SAN JUAN MOUNTAINS 393 
Ice formed in the cirques of the Silverton quadrangle and moved 
northward by the present site of the city of Ouray to a point fully 
ten miles downstream from that city where the ice ceased to 
advance and deposited a remarkable terminal moraine. This is 
e 
Bighorn ourwash 
Bighorn moraine 
q 
Sees e:?| 
Ke 
GLACIAL DEPOSITS 
in the 
RIO GRANDE VALLEY NEAR CREEDE 
Topography from San Cristobal quadrangle 
and Hayden Atlas 
Lf \ 2 3 4 Miles 
SAN ae ~ = 
za a iF 4 1500 feet 
Y CRs, \ _# ntour interval ee! 
Modified 
Bighorn moraine 
(9.5 0 
9,25 
) | San Juan moraine 
} 
f 
fer] 
102: 
bars 
Modified 
J San Juan moraine 
Uinta SSS 
the largest of the terminal moraines as yet described in the San 
Juan area; it is over 4oo feet in height’ and forms a crescentic 
ridge across the valley flat just northeast of the village of Ridgway. 
Near the headwaters of Dallas Creek, a tributary to the 
Uncompahgre from the west, there were small glaciers during the 
t Howe and Cross, Bull. Geol. Soc. Am., XVII (1906), 254-55; Cross and Howe, 
U.S. Geol. Survey, Folio 153 (1907), 7. ° 
