402 STANTON AND MARTIN — MESOZOIC SECTION ON COOK INLET 



tion of sandstones, and the fauna, except possibly a few species of 

 Belemnites and pelecypods, is entirely distinct. This part of the forma- 

 tion was studied by us at only two localities, namely, Snug harbor and 

 Enochkin bay. At Snug harbor the section exposed is much thicker 

 and more fossiliferous, being especially rich in Ammonites, which are 

 very scarce at Enochkin bay, but the two localities have enough com- 

 mon species to make the correlation of the beds positive. Many of the 

 Alaskan fossils described by Eichwald came from Snug harbor and a 

 large proportion of the species referred by him to the Neocomian and 

 the Gault came from this horizon. It was interesting also to find here 

 several species originally described by Whiteaves from Queen Charlotte 

 islands and supposed to have come from Cretaceous rocks. x\mong them 

 are Stephanoceras loganianum, S. Carlottense, Sphseroceras oblatum,S. cepoides, 

 and possibly Trigonia dawsoni, which are associated with Stephanoceras 

 cf. humphriesianum, several other species of Stephanoceras, Phylloceras, 

 Lytoceras, Lima cf. gigaatea, and many other forms in beds several thou- 

 sand feet below the top of the Jurassic. The most common fossils in 

 this zone are the several forms of Inoceramus described by Eichwald 

 as I. ambiguus, I. porrectus, I. eximius,, and I. lucifer, by means of which 

 the horizon has been recognized by collections obtained by Brooks and 

 Prindle in the Alaskan range near the headwaters of the Kuskokwim, 

 and its presence is suggested in the Kennicott formation of the Copper 

 River region by doubtful specimens in the collections of Schrader and 

 Spencer. 



A few fossil plants associated with the Ammonites have been identi- 

 fied by Doctor Knowlton as Sagenopteris goppertiana, Pterophyllum rajma- 

 halense, and Macrotxniopteris califomica. 



Hyatt examined a few fossils from Snug harbor and referred them to 

 the inferior Oolite or Middle Jurassic. No closely similar fauna has 

 been found elsewhere in Alaska or on the American continent, except 

 on the Queen Charlotte islands, where certain localities in the " Lower 

 Shales " have yielded Ammonites and a few other forms that evidently 

 belong to this fauna and have no connection with the Cretaceous fauna 

 from other localities on Queen Charlotte islands, supposed to be in the 

 same formation. Its exact correlation with European Jurassic faunas 

 must await the exhaustive study and description of the collections, but 

 it certainly includes at least a part of the Lower Oolite or Middle Jurassic. 



UPPER JURASSIC— NAKNEK FORMATION 



The Naknek formation was described by Spurr * from the vicinity of 

 Naknek lake and Katmai, on the Alaska peninsula. He says of it : 



*A reconnaissance of southwestern Alaska. Twentieth Ann. Rept. U. S. Geol. Survey, pt. 7, 

 1900, pp. 109-171. 



