1 88 ALASKA GLACIERS 



or varied by traveling dunes of lapilli. To my eye they 

 conveyed no impression of ice sculpture; I saw neither 

 the long parallel grooves and ridges which glaciers some- 

 times carve from homogeneous rocks, nor the groups of 

 moutonnee bosses which they usually develop where rocks 

 are of varied texture. On the main part of the island are 

 younger cones with well-preserved craters, and photo- 

 graphs show that with these are associated crags such as 

 an overriding glacier would not spare (fig. 89). Neither 

 is it to be supposed that the craters themselves would 

 survive the erosive action of a great ice-sheet. It may 

 be affirmed with confidence that if the island was ever 

 traversed by a glacier the crater-bearing cones are of 

 later origin. 



St. Matthew and Hall islands are also volcanic, but 

 without constructional forms. The period of eruption was 

 so remote as to give time for the complete subsequent re- 

 modeling of the surface by weathering and erosion. The 

 coast shows a succession of cliffs, with rare bays and 

 spits, and is evidently retreating rapidly before the attack 

 of the waves. The higher slopes, though sometimes 

 steep, are in general mature, and well adjusted to the con- 

 ditions of erosion in a climate which obstructs the flow 

 of water by clothing all surfaces with a sponge-like mantle 

 of mossy and herbaceous vegetation. I saw nothing of 

 the peculiar forms characteristic of glacial sculpture, but 

 noted, on the contrary, a few blunt pinnacles projecting 

 from the general surface and exhibiting such ragged de- 

 tails as one does not find in glaciated regions. Figure 90 

 represents one of these which happened to come within 

 the field of a photograph. 



The ordinary landing at Port Clarence is upon a long 

 spit, but we visited the mainland also, going ashore at a 

 point where a gently undulating surface rises within a 

 few miles to hills several hundred feet high. The rock is 



