PRINCE WILLIAM SOUND 1 75 



It is probable that Pleistocene ice occupied the whole 

 sound, but nothing is known of its seaward limit. 



In College Fiord, a branch of Port Wells already de- 

 scribed (page 81), there is a magnificent system of hanging 

 valleys, the larger being still occupied by glaciers, which 

 enter the fiord with ice cascades. These side glaciers 

 have accomplished something in the way of erosion since 

 the disappearance of the trunk glacier to which they were 

 once tributary, so that they do not rest upon the un- 

 modified face of the fiord wall, but occupy shallow chan- 

 nels. In a general way the surfaces of the glaciers, in 

 their lower courses, are flush with the adjoining portions 

 of the fiord wall. 



My attention has been directed by Gannett to the fact 

 that several of the cascading glaciers make two leaps, and 

 that there is a certain amount of harmony in the spacing 

 of the falls. When the region shall have been thoroughly 

 studied it is possible that the interpretation of these corre- 

 spondences may develop a special chapter in the history 

 of the ice retreat. 



With the aid of a series of photographs made by Mer- 

 riam, I have computed the approximate heights of the 

 more important cascades, as follows: Wellesley, 1,700 

 feet; Vassar, 2,200; Bryn Mawr, (trunk) 1,300, (left 

 branch) 2,700, (right branch) 2,500; Smith, 1,250, 1,700 



---- -B 



-JP 



Wall Vas. B M. Smith Rad 



FIG. 84. DIAGRAM OF NORTHWEST WALL OF COLLEGE FIORD. 



Short horizontal lines show the relative positions of the cascades of Wellesley, Vassar, 

 Bryn Mawr, Smith and Radcliffe glaciers. S.L. sea-level. Scale, 14,000 feet = i inch. Com- 

 pare figures 44 and 45. 



and 2,600; Radcliffe, 1,800 and 3,500. When these are 

 platted to scale in their proper vertical and horizontal re- 

 lations (fig. 84) they fall into two series, descending south- 

 ward from the head of the fiord. Making some allowance 



