martin.] GEOLOGY OF TOOK INLET REGION. 43 
Section on north sin, re of Oil Bay. 
Naknek formation : 
Arkose, andesite, sandstone, conglomerate, and shale___ . 2,000 
Sandy shale with Aucella near base 600 
Shale with fossils 380 
Coarse sandstone 3 
Shale with fossils 1G5 
Concealed 40 
Sandstone and sandy shale with plant impressions 310 
3,498 
Naknek formation?: 
Agglomerate with an abundance of small pebbles one-twelfth to 
one twenty-fifth inch in length, and with numerous poorly pre- 
served plant impressions 7 
Sandy shale and sandstone 85 
Agglomerate with pebbles as above 3 
Shale 1 
Fine agglomerate of same pebbles as above 7 
Fine agglomerate of same pebbles as above, but interbedded with 
shale 14 
Olive shale ° with an abundance of small pebbles as above 30 
147 
Enochkin formation : 
Dark shale with concretions 690 
Hard dark sandstone \-% 
Dark-drab shale with numerous concretions 530 
Calcareous shale with Cadoceras schmidti Pompeckj, Cadoceras, 
sp. cf. stenoloboide Pompeckj, and Phylloceras 1 
Dark shale 60 
Soft green sandstone I 
Dark-drab shale 12 
1,294 
The cliffs on the north shore of Chinitna Bay expose a thickness of 
many hundred feet of the upper part of the Enochkin shales. Exact 
measurements were not made here, so it is impossible to tell what pro- 
portion of the formation remains below water level. The cliffs south 
of the bay, on the landward escarpment of the coast range, also show 
a thickness of many hundred feet of the same rocks. Neither section 
has been studied in detail. 
Fossils are distributed throughout the entire thickness of the 
Enochkin formation, and show the age to be Jurassic. It consists of 
at least two well-marked paleontologic subdivisions. The lower 800 
or 1,000 feet contain several faunules, in which the pelecypods pre- 
dominate (zones A, B, and C), and which Dr. T.W. Stanton considers 
middle Jurassic. The upper 1,300 feet (zone D) are characterized 
Indeterminate fragments of a crustacean, evidently not related to the one from 
Bering Lake (see p. 14), were collected 5 feet above the base of this. 
