THE WORK OF SNOW AND ICE. 



257 



yond. In length they range from a fraction of a mile to many miles, 

 and though their width is usually much less than their length, the re- 



Fig. 235, — A glacier in the Cascades near Cascade Pass, Wash. A glacier inter- 

 mediate between a cliff glacier and a valley glacier. (Willis, U. S. Geol. Surv.) 



verse is sometimes the case (Figs. 233, 234, and 235). Their thickness is 

 usually measured by hundreds of feet rather than by denominations 



