GLACIATION IN THE TELLURIDE QUADRANGLE 511 
371, Mr. Capps refers to the striking similarity between the “rock streams” 
found at various points in the San Juan Mountains, and the “rock glaciers”’ of 
the Nizina region in Alaska. In regard to the latter he reaches the conclusion 
that they “‘are now in motion, moving in some such way as a glacier.” 
1910. Whitman Cross and Allen D. Hole.—In the Engineer Mountain Folio, 
pp. 8 and 9, evidences are given leading to the conclusion that the mountains 
of the quadrangle were subjected to glaciation at two distinct periods separated 
by a long interval of time. 
GLACIAL PHENOMENA OF THE QUADRANGLE 
As may be seen by reference to the literature cited above on 
glaciation in the region, complete detailed observations on the 
glacial phenomena of the Telluride quadrangle have not heretofore 
been made. By far the most complete account of such phenomena 
yet published is contained in the Telluride Folio, already referred to; 
but even there little reference is made to the details beyond what is 
necessary in illustrating general statements; and, moreover, 
especial attention is called to the fact that no attempt has been 
made to represent on the map all the deposits of glacial débris that 
were recognized. The overshadowing importance at that time of a 
careful study of the intricate relations involved in the volcanic 
rocks, and the demand for an early publication of the results of such 
study for the benefit of the extensive mining interests of the region 
no doubt fully justified the omission of many of the details relating 
to glacial action; the striking character, however, of some of the phe- 
nomena observed, and the aid which an understanding of the 
relations involved promised to give in the determination of some 
unsettled points in Quaternary history led to a systematic examina- 
tion of the glacial phenomena of the entire quadrangle, the report 
on which here presented constitutes, therefore, a supplement to the 
conclusions previously published. 
The evidences of glacial action found in the Telluride quadrangle 
include most of the characteristic marks of the work of glaciers as 
found in other localities, viz.: (1) cirques, (2) striated bed rock, 
(3) roches moutonnées, (4) lakes in rock basins, (5) moraines both in 
the form of ridges and of broad sheets with irregular, hummocky 
topography including undrained depressions, (6) unassorted drift 
including fragmental material of all sizes from fine silt to bowlders, 
