GLACIERS. 



685 



country, are sometimes preserved to the present time in great perfec- 

 tion. The view below, copied from the Report of Dr. Hayden for 



Fie. 1106. 



View on Roche-Moutonnee Creek, Colorado. 



1873, represents a portion of an immense crouching flock of them, 

 covering the side of the valley leading down from the " Mountain of 

 the Holy Cross," one of the prominent summits (12,485 feet high), in 

 the Crest range of the Rocky Mountains, Colorado ; they extend up 

 the slope for nearly 2,000 feet, and have suggested to Hayden & Gard- 

 ner, for the stream of the valley (a tributary of Eagle River, and that 

 of Grand River), the appropiate name of Roche-Moutonnee Creek. 



The furrowings or gougings have a direction corresponding with that 

 of the movement of the ice ; and sometimes two or more directions, 

 indicating glacier-movements of different periods. 



(3.) The stones which have produced the furrowing are smoothed, 

 polished on one or more sides, and often scratched. 



(4.) The grinding of the stones against one another, and those of 

 the bottom against the underlying rocks, produces very fine powder, 

 which makes the waters of the underflowing stream milky, and pro- 

 duces clay-like deposits (the bowlder clay). Lake Geneva owes its 

 blue color, according to Tyndall, to the presence of infinitesimal (gla- 

 cier-made) particles. 



Other facts connected with this subject are mentioned on page 531. 

 See also the works of Agassiz, Forbes, Tyndall, and Helmholtz. 



