BOUNDARY OF THE GLACIATED AREA. 177 



boldt range, local glaciers once existed in all the higher por» 

 tions. In some of the valleys they extended for seven or 

 eight miles. In Utah the Wahsatch Mountains were the 

 chief center of local glaciers. The principal mountain- mass 

 is about fifteen miles wide, and peaks above 10,000 feet high 

 are numerous. Th? glaciers formerly radiating from this 

 mass did not, however, reach a very low level. In Colorado 

 there are evidences of former glaciers only above the 10,000- 

 foot line. Beyond that line, such valleys as those occupied 

 by the head-waters of the Platte and Arkansas Rivers were 

 once filled with glaciers whose terminal moraines, in some 

 cases, formed dams of great extent, and thus gave rise to 

 temporary lakes. The most southern point at which signs 

 of local glaciers in the Rocky Mountains have been noted is 

 near the summits of the San Juan Range in southwestern 

 ColoradOo Here a surface of about twenty-five square miles, 

 extending from an elevation of 12,000 feet down to 8,000 

 feet, shows every sign of the former presence of moving ice. 

 Northward of Utah and Colorado the signs of former glacia- 

 tion are also of the same local character — that is, glaciers 

 everywhere radiated from the higher mountain-masses, and 

 extended a short distance down the canons and valleys. The 

 Upper Canon of the Yellowstone, in the famous park, was 

 filled with glacial ice to a depth of 1,600 feet, and glacial 

 marks were abundant down to the vicinity of Livingston. 



The glaciers of the Sierra Nevada and Cascade Range in 

 California, Oregon, and State of Washington were on a 

 much grander scale than those in the Rocky Mountains; 

 but, in the one case as in the other, the glaciated areas are 

 local, and, except in the state of Washington, not connected 

 with the grand movement farther north. 



Upon this point Mr. Clarence King, who had most care- 

 fully explored the region, writes : 



In the field of the United States Cordilleras, we have so 

 far failed to find any evidence whatever of a southward-mov- 

 ing continental ice-mass. As far north as the upper Colum- 



