RUGGED AND CONFUSED TOPOGRAPHY. 139 



There is an interesting feature in the contour of the mountains forming 

 the most conspicuous portion of Amaknak island, which may have some 

 connection with former glaciation. The lower slopes have a rounded and 

 flowing outline, due in part to their mossy covering, which is limited in the 

 upper portion of the mountain by an irregular scarp. Above the scarp the 

 mountain slopes are steeper and more angular than below. It may be that 

 the scarp referred to marks the upper limit of former glaciation. Another 

 suggestion is that it is an ancient sea-cliff. This record and suggestion is 

 made with the hope that some one having opportunity may be stimulated to 

 investigate the phenomena more fully* 



From the summit of Mount Wood, mentioned above, a magnificent view 

 can be had on clear days of one of the most rugged landscapes that can well 

 be imagined. The impression that one receives from such a wide-reaching 

 view of Unalaska is that its topography is without system. The more one 

 studies the forms of the laud the stronger this impression becomes. The 

 island is without the orderly arrangement of valleys usually so characteristic 

 of well-drained districts in humid regions. There are bold cliffs and out- 

 standing buttes which bear evidence of orographic disturbances and of long 

 exposure. I was not able to detect auy evidence in the relief of the land of 

 the former presence of a general ice sheet, nor was I more successful in at- 

 tempting to trace the paths of ancient Alpine glaciers. The topography of 

 the island is chaotic. Ragged cliffs, shattered peaks, together with walls and 

 spires of naked rock, rise on every hand, but without orderly arrangement. 



I suspect that the reason for the confused and exceptional character of 

 the topography is due in large part to the obstruction offered to erosion by 

 the mossy covering of the lower portions of the island. The rain that falls 

 in the region of the Aleutian islands and in Alaska generally partakes of 

 the character of " Scotch mists " rather than of tropical down-pours. This and 

 the fact that a very large part of the annual precipitation is in the form of 

 snow would indicate that the impact of rain drops, an important factor in 

 the erosion of many regions, is here reduced to a minimum. 



From Mount Wood one sees the majestic snow-clad summit of Makooshin 

 against the western sky. Across Akutan pass, to the east, is another active 

 volcanic cone of surprising beauty, rising above the sea mist like a cone of 

 burnished silver far into the clear heavens. To the north of Captain s 

 harbor is the extinct volcanic crater known as Paistrakov, thesides of which 

 have scarcely been scored by erosion. These mountains, formed by volcanic 



*It may be well in this connection to direct attention to certain oliscure jii<li. ;l ti;.n- of terraces 

 or sea-cliffs, at an elevation of fifteen hundre.i or two thousand feet, on a number ol the mountains 

 near the Yukon, below Nulato. None of these mountains have been closely exam id it I 



impossible to state whether the indefinite lines which may indicate terraces are horizontal, or 

 whether they coincide in elevation. It is not safe to assume that they are terra "le 



that they may indicate lines of structure or be due to landslides, rhe mountains are so situated 

 that they could not have retained a lake, and if water lines exist on them their origin must be 

 looked for in a submergence of the land. 



XIX— Bull. Geol. Soc. Am., Vol. I, 1889. 



