SECTION OF ENOCHKIN FORMATION 401 



Feet 



Indurated bands of argillaceous sandstone with abundant specimens of 



Cadoceras and Belemnites 10 



Dark shales and argillaceous sandstones 115 



Similar beds not well exposed 200 



Dark shales weathering to brownish slopes with bands of small concretions 



containing Cadoceras doroschini, etcetera 330 



Similar shales mostly covered 75 



Dark clay shales weathering brownish with concretions containing Cado- 

 ceras, etcetera, near middle 110 



Total 2,415 



This section, like that at Oil bay, contains no beds lower than zone D, 

 and it is overlain by an immense thickness of the Naknek formation. 

 No fossils were found in the upper 1,000 feet or more which are assigned 

 to the Enochkin formation on lithologic grounds. 



The Enochkin formation, as defined and described in the preceding 

 pages, might well be divided into two formations, differing somewhat 

 lithologically. and each characterized by a distinct fauna. In the upper 

 two-thirds shales predominate, and the most characteristic fossils are 

 several species of Cadoceras. This portion, which we have mentioned 

 as u zone D " or the " Cadoceras zone," has been recognized by its fossils 

 from Snug harbor to Cold bay. Its characteristic Ammonites have been 

 assigned to the Callovian by Neumayr, Hyatt, and Pompeckj, all of 

 whom recognized the character of the fauna, which is represented by 

 closely similar forms in Russia, Franz Josef Land, and elsewhere in 

 northern regions, as well as in other parts of Europe. This Callovian 

 fauna is placed by many geologists in the lower part of the Upper 

 Jurassic, but it seems to accord better with the local development in 

 Alaska to follow the custom of some German geologists and assign it to 

 the top of the Middle Jurassic. Seven species of Cadoceras have been 

 named from Alaska, some of which will evidently become synonyms 

 when the large collections now on hand are fully studied, and possibly 

 one or two additional names will be necessary. With these are asso- 

 ciated Sphseroceras, Phylloceras, and one or two other genera of Ammo- 

 nites, Belemnites, and a very few pelecypods and gastropods. A few 

 plants, referred by Dr F. H. Knowlton to Cladophlebis denticulata, Ctenis 

 grandifolia, Hausmannia sp., and Dictyophyllum cf. D. obtusilobum, have 

 been found with the marine invertebrates. In addition to the localities 

 on Cook inlet and the Alaska peninsula, Pompeckj has described several 

 species of Cadoceras in an early Russian collection, said to have come 

 from the " Sotkin'sches Ufer " of Kodiak island, but it is possible that 

 the locality given is erroneous. 



The lower third of the Enochkin formation contains a larger propor- 



