406 STANTON AND MARTIN — MESOZOIC SECTION ON COOK INLET 



This section is given in detail on account of the very great apparent 

 thickness of the rocks referred to the Naknek formation. It is possible 

 that a part of this thickness may be due to repetition of beds by faulting, 

 though we were unable to detect any repetition and the faults seen did 

 not seem to be important. Fossils are not abundant, but the character- 

 istic Aucella resembling A. pallasi was found sparingly both near the 

 top and near the bottom of the formation. 



Section of Naknek formation on east shore of Oil bay, Alaska 



Naknek formation : Feet 



Arkose, andesite, sandstone, conglomerate, and shale 2,000 



Sandy shale with Aucella near base 600 



Shale with fossils 380 



Coarse sandstone 3 



Shale with Cardioceras, Astarte, etcetera 165 



Concealed 40 



Sandstone and sandy shale with Lytoceras, Phylloceras, and plant im- 

 pressions 310 



Naknek formation (?) : 



Agglomerate with an abundance of small pebbles, one-twelfth to one 

 twenty-fifth of an inch in length, and with numerous poorly preserved 



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 



Shale (Enochkin formation) 



Total . 3,645 



These exposures are shown in plate 68, figure 1. 



Section of Naknek formation on east shore of Enochkin bay 



Feet 



Sandstone, arkose, shale, andesite flows, and agglomerate 270-f- 



Dark sandy shale, with Aucella in upper part 583 



Coarse agglomerate , . 290 



Shale (Enochkin formation) 



Total 1,143 



The coarse agglomerateTorming the lower 290 feet of the last section 

 is regarded as a local lens. It was also seen in the same position on 

 Chisik island. The fine pebble agglomerate extending through a local 

 thickness of 147 feet in the Oil Bay section is regarded as probably the 

 representative of the coarser beds seen elsewhere. This section forms 

 the upper two-thirds of the cliffs shown in plate 69, figure 1. 



