S. H. Soworth — Elevation of American Cordillera. 443 



(essence identical with the Andes. I do not include the so-called 

 Coast Eange or the Cascade Mountains, or the Selkirk Eange, or the 

 Sierra Nevada. On all these there are traces of glacial action on 

 a considerable scale ; but in the case of the dominant range this is 

 not so, and, except on some of the higher peaks, where the phenomena 

 may have a very recent origin, there is a very singular absence of 

 such phenomena. 



In such a matter I cannot quote any one better than Mr. Clarence 

 King. He writes : 



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

 failed to find any evidence whatever of a southward-moving con- 

 tinental ice-mass. As far north as the Upper Columbia, and 

 southward to the Mexican boundary, there is neither any boulder 

 clay nor scorings indicative of a southward-moving ice-mass. On 

 the contrary, the great areas of Quaternary material are evidently 

 subaerial, not subglacial. The rocks outside the limit of local 

 mountain glaciers show no traces either of the rounding, scoring, 

 or polishing which are so consjoicuously preserved in the regions 

 overridden by the northern glacier. Everything confirms the 

 generalization of Whitney as to the absence of general glacia- 



tion Not more than a thirtieth part of the entire surface 



of the fortieth parallel area was ever covered by glacial ice 



Whatever the greater causes may have been, the Cordilleran surface 

 south of Washington Territory was free from an ice-sheet, and the 

 only ice-masses were small areas of local glaciers which did not 

 cover two per cent, of the mountain country." 



Whitney also tells us that in the interior parts of the Cordillera 

 the ancient glaciers usually extended down to about 7000 or 8000 

 feet above the sea (United States Geol. Expl. of the 40th Parallel, 

 pp. 459-461 and 464). 



In Dr. Wright's recently published " Ice Age in North America," 

 we read : 



" According to Whitney there are no signs of ancient glaciers 

 in Western Nevada, though some of the mountains rise to a 



height of 10,000 feet In Colorado there are evidences of 



ancient glaciers only above the 10,000 foot line The most 



southern point at which signs of local glaciers in the Eocky 

 Mountains have been noted is near the summits of the San Juan 

 Eange, in South-Western Colorado. Here a surface of about 

 25 square miles, extending from an elevation of 12,000 feet down 

 to 8000 feet, shows every sign of the former presence of moving 

 ice. Northward of Utah and Colorado the signs of former glaciatioa 

 are of the same local character ; that is, glaciers everywhere radiated 

 from the higher mountain masses, and extended a short distance 



down the caiions and valleys The glaciers of the Sierra 



Nevada and Cascade Eange in California, Oregon and Washington 

 Territory were on a much grander scale than those in the Eocky 

 Mountains" {op. cit. pp. 148, 149). 



Professor George Dawson, in criticizing some of Prof. Whitney's 

 views, says : 



"The general result arrived at in the areas of Whitney's and 



