724 ALLEN DAVID HOLE 
be present as of minor importance. So far as the observations 
made by the author of this paper in the Telluride quadrangle give a 
basis for conclusions, it appears that these accumulations of rock 
fragments are due primarily to the work of ice as indicated by 
Capps in the article just referred to. The reason for assigning 
this cause as the principal one in the case of the rock streams in this 
quadrangle may be summed up from the descriptions already given 
as follows: 
1. The topography of the surface, consisting of irregularly dis- 
posed ridges and kettle-like depressions. 
2. The steep slope of the outer boundary, formed of fragments 
insecure In position, showing that they have been but recently 
moved to their present place. 
3. The considerable distance which much of the ater has 
been moved from the cliff from which it has been derived. 
4. The location of these areas at elevations practically the same 
as that at which crevassed mévé ice was reported ‘‘on the north slope 
of the high ridge east of Dallas Peak.’’* When this slope was visited 
in August, 1905, no mass of ice was visible, but rock streams were 
observed both on the north slope of this ridge and over the divide 
east of Gilpin Peak. 
5. The location of a considerable number of the rock streams in 
positions where snow and ice would be most likely to accumulate 
in large amount, and likely also to be best protected from the sun’s 
rays. The larger areas are, of course, found in positions directly 
exposed to the rays of the sun, but the smaller ones are far more 
abundant at the foot of northward-facing, or pear as 
precipitous slopes. 
6. The relation in position of the rock streams of two distinctly 
different periods of movement in which the later appear to have 
moved around the earlier, deploying after passing the latter as in 
the case of actual glacial movement. 
If the interpretation here given of the above phenomena is 
correct, the rock streams in this quadrangle are to be considered as 
representing incipient glacial movement. With respect to the last © 
period of glaciation such movements are clearly to be regarded as 
t Telluride Folio, p. 15. 
