HARRIMAN FIORD 89 



They are separated from the ice, first by a broad belt of 

 alders, and then by a barren zone. As the spruce forest 

 in College Fiord nowhere stands close to the ice, but is 

 separated by a barren zone, it seems fair to assume that 

 the ice has occupied this zone so recently that the period 

 since its shrinkage has not sufficed for reforesting; but no 

 facts are recorded tending to show the nature of the 

 changes immediately preceding our visit. 



The four tidal glaciers on the northwest side of the 

 fiord, and four branches of the Harvard reaching it from 

 the same mountain range, show a remarkable agreement 

 in certain general features of profile. Near their de- 

 bouchure they descend in one or more steep cascades 

 through a vertical space of 1,700 to 3,000 feet, and back 

 of these cascades their slopes are comparatively gentle. 

 Their upper valleys are deeply incised, but their lower 

 valleys are shallow, barely sufficing to hold the ice 

 streams, so that the faces of the glaciers are nearly flush 

 with the general face of the fiord wall. These features 

 indicate that the principal work of ice sculpture was per- 

 formed when the trunk glacier filled the fiord to a level 

 somewhat above the line of cascades. It was then that 

 the fiord wall received its smooth contours, and much of 

 the general excavation of the fiord may have been per- 

 formed at the same time. The tributary ice streams from 

 the side carved shallower troughs, adjusted to their needs, 

 and were prevented from excavating deeply at any point 

 because the great trunk glacier gave them a high base- 

 level of discharge. These tributary troughs will receive 

 further consideration in the chapter on Pleistocene glacia- 

 tion. 



HARRIMAN FIORD 



From the bend where it is joined by College Fiord 

 Port Wells extends only three or four miles northward 

 and is reduced in width. Its trough then swings quickly 



