EXTINCT AND EXISTING GLACIERS OF COLORADO 59 



of La Plata, Dolores and Rio Grande." The Conejos and Archuleta 

 County (Endlich, p. 220) glaciation should be included in the list. 

 He also says the greatest lateral glacier flowing into the Rio Grande 

 Valley was Clear Creek, and that the Lost Trail and Timber Hill 

 country was all glaciated. Stone says every cirque of the tributaries 

 of the Las Animas above Silverton contained glaciers connecting 

 with the main one. In La Plata Quadrangle, according to Cross and 

 Spencer, "the only deposit of distinctly glacial material which has been 

 recognized is a small terminal moraine across the valley of the La 

 Plata at old Parrott City." SaHsbury reports small glaciers on the 

 north side of Spanish Peaks. Many glaciers existed in the tributaries 

 of the Gunnison (Stone) . In Uncompahgra Valley the lowest moraine 

 is between Ridgway and Dallas, altitude 7,000 feet, eight miles beyond 

 the mountains — a terminal moraine 400 feet high and over two miles 

 long (Stone and Howe and Cross). In San Miguel Valley, the North 

 Fork Glacier reached Keystone, about five miles west of Telluride. 

 The glaciers of Ophir and Trout Lake basins on South Fork were 

 probably less than eight miles long (Stone) . On Bridalveil Creek a 

 thickness of 2,000 feet of ice is indicated (Cross and Howe, Ouray Folio, 

 p. 15). The "Great Amphitheater" was ascribed by Endlich to the 

 sinking of the floor of the valley for more than 2,000 feet, but Cross 

 {Telluride Folio, p. 9) found no evidence of such subsidence and believes 

 that it was formed "by the same agents of erosion that produced all 

 the other basins of the region." In the Rico Mountains "all the 

 facts available point to the very local nature of the glaciation .... 

 and to the short duration of glacial conditions" (Spencer). Glaciers 

 occurred in Silver Creek Valley and its tributaries, Deadwood Gulch, 

 and on the tributaries of Scotch Creek. 



Sangre de Cristo Range. — Endlich^ saw "small indications of 

 local glacial action . . . . . in some of the canyons of the Sangre de 

 Cristo Range," and was not certain as to their glacial character. 

 Stevenson^ described Grape Creek Glacier on the east slope. Sieben- 



■ Endlich, F. M., "Ancient Glaciers in Southern Colorado," Ninth Ann. Kept. U.S. Geol. and Geog. 

 Surv. Terr., for 1875, p. 220, 1877. 



' Stevenson, John J., "Geology of a Portion of Colorado Explored and Surveyed in 1873," Geog. and 

 Geol. Explor. and Surv. W. of loolh Meridian, Vol. Ill, pp. 434-35- 



