74 ALASKA GEOLOGY 



and dying out on either side slope. These terraces aver- 

 age about three feet in width, with two or two and a half 

 feet rise between them; their surfaces are very level and 

 paved with angular fragments of rock, not lying loose 

 but firmly embedded in sandy material. The front slopes 

 are densely covered with grass and other matted plant 

 growth so that the appearance, looking up the slope, is 

 of a continuous grassy covering, while looking down, all 

 appears rocky and bare. The terraces often run from 

 side to side of the slope without break, but again they 

 anastomose like cow paths on a hillside. The down- 

 ward shifting of the slide rock against the resistance of 

 the matted plant covering would probably sufficiently 

 account for the terrace structure, but the curiously even 

 paved surface of the terraces was to me inexplicable. 



The summits of the higher peaks are angular and 

 craggy, and nowhere was any evidence seen of glacial 

 action even of a local nature. 



The rocks occupying most of the area studied about 

 Chichagof Cove (see fig. 17) are a series of marine sedi- 

 ments containing abundant fossil remains, which show 

 them to be of Lower Eocene age. To this series the 

 name Stepovak Series will be applied. The beds have 

 been considerably folded and faulted, and invaded by a 

 laccolithic intrusion of diorite-porphyrite, which sends off 

 into the surrounding sediments numerous radial dikes of 

 varying petrographic character. 



THE STEPOVAK SERIES 



The Stepovak Series may be divided on lithologic 

 grounds into upper and lower beds. 



The lower beds comprise coarse breccias or agglomer- 

 ates and fine tuffs composed wholly of igneous material. 

 They show only a rude stratification, but as far as it can 

 be made out it is accordant with that of the overlying, 



