DESCRIPTION OF THE ROCKS 699 



part of the sequence is of Karnic age and is to be correlated approximately 

 with at least part of the Chitistone limestone of the Chitina Valley and 

 of the Hosselkus limestone of California. The writer would suggest, 

 however, that this Halobia, and possibly also the one that has been ob- 

 tained from the west coast of Cook Inlet, may belong to the species which 

 Stanton has noted 17 in the lower part of the Brock shale of California, or 

 possibly to one of the species 18 that occur in the Lower Noric beds of Ore- 

 gon. If this be the case, the occurrence of Halobia in these beds does not 

 necessarily indicate that they are the equivalent of the Chitistone lime- 

 stone or that they are older than the supposed ISToric strata of California. 

 The contorted cherts of Kenai Peninsula (see plate 28, figure 1) have 

 yielded no characteristic fossils and their age is somewhat doubtful. The 

 local field relations indicate that the cherts lie immediately above the 

 ellipsoidal lavas and beneath the limestones and tuffs, which seem to occur 

 directly beneath the Lower Jurassic beds and to be the youngest Triassic 

 rocks in the local section. This sequence accords well with the relations 

 of similar beds in other regions, provided that the Halobia belongs to a 

 species whose range is such that the limestones and tuffs can be corre- 

 lated with the McCarthy formation and with the upper part of the Kami- 

 shak chert, and that the cherts can be correlated with the cherts at the 

 base of the McCarthy and Kamishak formations. But if the Halobia is a 

 strictly Karnic species which is restricted to the horizon of the Chitistone 

 limestone and of the lower part of the Hosselkus limestone, the lower part 

 of the limestones and tuffs must be correlated with rocks occurring be- 

 neath the cherts at the base of the McCarthy and Kamishak formations, 

 and the cherts can not be considered as occurring beneath the limestones 

 and tuffs of Port Graham and be correlated with any of the Triassic cherts 

 known in other Alaskan districts. The writer believes that this Halobia 

 is probably not an exclusively Karnic (lower Hosselkus) species, and that 

 the cherts of Kenai Peninsula should be regarded as occurring beneath 

 "the limestones and tuffs and above the ellipsoidal lavas, and should be 

 correlated with the cherts at the base of the McCarthy formation and 

 with the lower part of the Kamishak chert. 



The Upper Triassic rocks of the Alaska Peninsula 19 include limestone 

 and shale, 700 feet or more in thickness, containing Pseudomonotis sub- 



17 T. W. Stanton, cited by J. S. Diller : Redding folio (No. 138),' Geol. Atlas. U. S. 

 Geol. Survey, 1906, p. 5. 



1S James Perrin Smith : The occurrence of coral reefs in the Triassic of North America. 

 Am. Jour. Sci., 4th ser., vol. 33, 1912, p. 95. 



in P. Fischer : Sur quelques fossiles de 1' Alaska. Voyages a la cote nord-ouest de 

 l'Amerique, pt. 1, 1875, pp. 33-36, pi. A. 



T. W. Stanton and G. C. Martin : Mesozoic section on Cook Inlet and Alaska Penin- 

 sula. Bull. Geol. Soc. Am., vol. 16, 1905, pp. 393-396. 



