28 ALASKA GEOLOGY 



which contains angular fragments of the darker rock. 

 In many places both rocks are much epidotized, and veins 

 of quartz-epidote rock (137) form large irregular masses 

 in great abundance. Veins of coarse white aplite cut 

 both of the above rocks, and this aplite proved to be of an 

 exceptional variety, containing as its only bisilicate con- 

 stituent a colorless pyroxene, and properly termed a py- 

 roxene-aplite (136). 



ALASKA PENINSULA AND SHUMAGIN ISLANDS 



A zoological collecting party from the steamer, which 

 spent some days at Kukak Bay on the mainland of the 

 Alaska peninsula north of Kadiak Island, brought back an 

 extensive collection of beautifully preserved fossil plants 

 which are described elsewhere in this report. With the 

 plant-bearing rocks, which appeared to be shales or fine 

 ash beds, were brought coarse conglomerate and grits, 

 containing limestone concretions, and said to overlie the 

 plant beds. There were also coarse tuffs and specimens of 

 altered augite-andesites, which were said to be very abun- 

 dant at the locality. The relation of these rocks to the 

 sedimentary beds was not determined. The series doubt- 

 less belongs to the Kenai Group of Dall, which is widely 

 distributed along the peninsula. 



We admired at a distance, and with exceptionally clear 

 weather, the great volcanic mountains from Redoubt and 

 Iliamna high up in Cook Inlet to Makushin on Unalaska 

 Island, and had especially fine views of the wonderfully 

 symmetrical Pavlof (frontispiece) and the grand Shishal- 

 din. Steam seemed to be issuing from the spot high up 

 on the main peak of Pavlof (the nearer peak in plate in), 

 where the snow had apparently been removed by the heat. 

 Great columns of steam could be clearly seen rising from 

 the valleys low down the mountain and near the sea on 

 the south and southeast slopes of the nearer peak. 



