138 



CRUISE OF STEAMER CORWIN IN THE ARCTIC OCEAN. 



that, with the exception of the recent craters, almost every existing feature is distinctly "Glacial. 

 The comparative featureless pre-Glacial rocks have been heavily sculptured and fashioned iuto the 

 endless variety they now present of peak and ridge, valley and fiord and clustering islets, harmo- 

 niously correlated iu accordance with glacial law. 



OVERSWEPT MOUNTAINS, WITH PAKALLEL VALLEYS AND RIDGES, FROM 20 MILES NORTHWEST OF EAST CAPE. 



On Mount Makushin, whose summit reaches an elevation of about 9,000 feet above the sea, 

 several small glaciers still exist, while others yet smaller may be hiddeu in the basins of other 

 mountains not yet explored. The summit of Makushin at the time our observations were made 

 was capped with heavy clouds, and from beneath these the glaciers were seen descending impos- 

 ingly into the open sunshine to within 1,000 or 1,500 feet of the sea level, the largest perhaps 

 about miles in length. After the clouds cleared away the summit was seen to be heavily capped 

 with ice, leaving only the crumbling edges of the dividing ridges and subordinate peaks free. 

 The lower slopes of the mountain and the wide valleys proceeding from the glaciers present 

 testimony of every kind to show that these glaciers now lingering on the, summit once flowed 

 directly into the sea ; and the adjacent mountains also, though now mostly free from ice, are covered 

 with Glacial markings, extending over all the low grounds about their bases and the shores of the 

 fiords and over many of the rocks now under water, lint besides this evidence of recent local 

 Glacial abundance, we find traces of far grander Glacial conditions on the heavily abraded rocks 

 along the shores of the passes separating the islands, and also in the low wide-bottomed valleys 

 extending in a direction parallel with the passes across the islands, indicating the movement of a 

 vast ice sheet from the north over the ground now covered by Bering Sea. 



The amount of degradation this island region has undergone is only partially manifested by 

 the crumbling, sharpened condition of the ridges and peaks, the abraded surfaces that have, been 

 overswept, and by the extent of the valleys and fiords, and the gaps between the mountains and 

 islands. 



That these valleys, fiords, gorges, and gaps, great and small, are not a result of local subsi 

 deuces and upheavals, but of the removal of the material that once filled them, is shown by the 

 broken condition and the similarity of the physical structure and composition of their contiguous 

 stiles, just as the correspondence between the tiers of masonry on either side of a broken gap in 

 a wall shows that the missing blocks required to fill it up have been removed. 



The chief agents of erosion and transportation are water and ice, each being regarded as the 

 more influential by different observers, though the phenomena to which they give rise are widely 

 different. All geologists recognize the fact that glaciers wear away the rocks over which they 

 move, but great vagueness prevails as to the size of the fragments of erosion, and the way they 

 are detached and removed; and if possible still greater vagueness prevails as to the forms and 

 characteristics iu general of the mountains, hills, rocks, valleys, &c, resulting from this erosion. 

 Towards the end of summer, when the snow is melted from the lower portions of the glaciers, 

 particles of dust and sand may be seen scattered over their surfaces, together with angular masses 

 of rocks, derived from the shattered storm-beaten cliffs above their fountains. The separation of 

 these masses, which vary greatly iu size, is due only in part to the action of the glacier, though 

 they are all transported on its surface like floatiug drift on a river, and deposited together in 

 moraines. The winds supply a portion of the sand and dust, some of the larger fragments are 



