6o UNIVERSITY OF COLOILA.DO STUDIES 



thai' says the glaciers on the west side of the range just reached down 

 to the alluvial slopes of San Luis Valley, and that most of the streams 

 heading against the crest of the range on both sides held glaciers. He 

 especially refers to Black Canyon, Willow Creek, South Zapate, 

 Middle Creek and Bear Creek. The glaciers of this range formerly 

 descended to 9,000 or 9,500 feet. 



Existing Glaciers of Colorado 

 Arapahoe Glacier.— Lee published the first account of this glacier 

 in 1900.^ The summer of 1902 being an unusually favorable season 

 for observation, I visited it late in August with Dr. N. M. Fenneman 

 and Mr. H. F. Watts, and we made a careful survey and study of the 

 ice and the general glaciation of the region.^ Since then I have made 

 observations on September i of almost every year, to ascertain to 

 what extent, if any, it was receding, and in 1904 and 1905 Mr. Watts 

 and I measured the rate of motion." 



This, though small, is a typical alpine glacier, having all the char- 

 acters of the great alpine glaciers of the world, and is the most impor- 

 tant ice-body yet discovered in Colorado. It is perhaps the only one 

 whose title may not be disputed by some glacialists. Possibly it has 

 only been within recent years that the snow line has receded in summer 

 far enough to disclose its real character. A search for old photo- 

 graphs which might settle this point has been fruitless. 



It is situated in the cirque on the east side of the Arapahoes, at the 

 head of North Boulder Canyon, in plain sight from Boulder. The 

 chief source of the ice is the south cliff at the head of the cirque or 

 amphitheater. It moves first northward, then eastward and finally 

 southward. Only a portion is seen from Boulder and mostly with 

 a side view, which minimizes the impressiveness of the sight. The 



- SiEBENTHAL, C. E., "The San Luis VaUey, Colorado," Science, N.S., Vol. XXXI, pp. 744-46, 1910; 

 "Notes on Glaciation in the Sangre de Cristo Range, Colorado," Journ. GeoL, Vol. XV, pp. 15-22, 1907; 

 Geology and Water Resources of the San Luis Valley, Colorado, U.S. Geol. Surv., Water-Supply Paper No. 240, 

 p. 46, 1910. 



' Lee, Wilus, T., "The Glacier of Mt. Arapahoe, Colorado," Journ. Geol., Vol. VIII, pp. 647-54, 1900. 



» Fenneman, N. M., "The Arapahoe Glacier in 1902," Journ. Geol., Vol. X, pp. 839-51, 1902. 



* Henderson, Junius, "Arapahoe Glacier in 1903," Journ. Geol, Vol. XII, pp. 30-33, 1904; "Arapahoe 

 Glacier in 1905," Journ. Geol., Vol. XIII, p. 556, 1905; "A Colorado Glacier," Harper's Monthly, Vol. CXII, 

 pp. 609-14, 1906. 



