ATKA ISLAND AND OTHERS TO THE WESTWARD. 121 



already quoted (pages 243-244), from which it appears that in Karovinski 

 bay, on the west side of the island, pieces of fossil wood, sometimes silici- 

 fied, as well as marine Miocene fossils in tiifFaceous volcanic deposits, are 

 found. The little islands in Nazan bay and the low projecting points 

 about it have a basaltic appearance and rather irregular columnar 

 structure. The rock showing on the beach, at the village, is a greenish 

 gray, fine grained material, very hard and in places containing many 

 grains of iron-pyrites, probably clastic and apparently a diabase, though 

 not microscopically determined. It is also traversed by small drusy 

 veins of quartz, and large loose masses of quartz were found which had 

 evidently not travelled far. 



In a small brook, which has cut out a little ravine near the village, a 

 considerable depth of superficial earthy material is exposed. This ex- 

 hibits a certain amount of stratification i)arallel to the slope of the 

 ground. It is brownish or reddish brown in color, and appeared to be 

 composed of volcanic detritus, which has either been deposited in the 

 sea when the land was at a somewhat lower level, or perhaps more 

 probably merely washed down the slopes while in an incoherent and 

 fresh state. Material of the same kind was recognized elsewhere on 

 this and other itslands of the Aleutian chain, sometimes in rather notable 

 quantity. 



No indications of old terrace levels were observed about Nazan hsij, 

 but around the base of the mountain which forms a projecting point to 

 the north of the entrance of the bay, three or more successive, indistinct 

 terrace-like markings occur, the highest being at an elevation of about 

 1,000 feet above the present sea level. These markings may represent 

 old beachlines impressed in soft material, but from their indefinite 

 character this remains uncertain. 



Gi^eat SitJcin Island. — After j)assing Atka island a fine general view of 

 Great Sitkin island was obtained. This evidently consists of a single 

 large volcanic cone, which, according to the charts, is still 5,033 feet high. 

 Its upper portion was heavily covered with snow. 



Bnldir Island. — Buldir island was passed sufficiently near to enable 

 it to V)e well seen. Its eastern end is most elevated, and high cliffs there 

 show a series of flows or beds of volcanic material, dipping rather steeply 

 westward. The angle of dip gradually diminishes and the stratification 

 becomes horizontal at the west end of the island, the general height of 

 the surface decreasing in a corresponding degree. The whole island 

 clearly represents the residual portion of an originally symmetrical vol- 

 canic mountain, the greater part of which has been cut away by the sea. 



Semichl Islands.— The Semichi islands form a narrow chain, broken by 

 two small gaps, and about fourteen miles in total length. They are un- 



