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 Dali, 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 111), 
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. 
