THE WORK OF SNOW AND ICE 



253 



will abrade the same surface notably. The effect of this abrasion 

 is shown in the grooves and scratches (strice) which the stones in 



Fig. 204. Striae, grooves, etc., in a canyon tributary to Big Cottonwood 

 Canyon, Wasatch Mountains. (Church.) 



the bottom of the ice inflict on the surface of the rock over which 

 they pass (Figs. 203 and 204). At the same time, the stones in the 

 ice are themselves worn both bv abrasion with the bottom, and 



Fig. 205. Stones striated by glacial wear. 



