CHICHAGOF COVE 77 



parison with those found in the higher beds. But they 

 establish the fact that some of the tuffs at least are water- 

 laid deposits, however little the rocks themselves might 

 suggest that conclusion. 



The upper beds consist of soft shales, sandstones and 

 grits, with some thin beds of limestone and now and then 

 a chert band. They are the principal rocks of the region, 

 and make up the whole coast line of the area studied. 

 The following sections of these beds were noted, and will 

 serve to indicate the character of the rocks in different 

 portions of the area. 



GEOLOGICAL SECTIONS 



East Point of Chichagof Cove. Strike N 65 E (true), dip S 

 25 E, about 45. Dip uniform through the whole section. Alter- 

 nating bands of soft black shale and fine-grained sandstone, the shale 

 more abundant in the lower part of the section. One bed of coarse 

 grit, but no conglomerate. Some of the shale is reddish from abun- 

 dant limonite, and both shale and sandstone in certain layers include 

 small limestone concretions, rarely containing fossils. The fossils are 

 chiefly casts in massive beds of sandstone occurring in the upper part 

 of the section. On exposed surfaces the sandstone breaks up into 

 lenticular masses with uneven, curved parting surfaces. The section 

 was not measured, but was estimated at not less than 1,000 feet in 

 thickness. 



West Point of Chichagof Cove. Strike N 80 E, dip S 10 E 

 about 20, flattening a little to the west. The base of the section is of 

 soft shale, some layers containing limestone concretions, others sparse 

 pyrite nodules. Above these are heavy -bedded sandstones, gray to 

 greenish gray in color, with numerous, rather scattered fossils. In 

 some places the sandstone is full of concretions, from three inches to 

 one foot in diameter, which were not found to contain fossils. 



Chichagof Peak. Resting on the lower pyroclastic beds at the 

 base of the mountain is a considerable thickness of soft black shale 

 containing a few fossils ; near the contact of the dikes which cut it, it 

 is baked and silicified. Above the shale is cross-bedded sandstone, 

 highly silicified, in which no fossils were discovered. Above this are 

 beds of rusty red shale, with occasional layers of sandstone, to the sum- 



