| The Jurassic collections from the Union Oil Company represent a number of the standard European stages. The Lower Jurassic (Toarcian) is probably represented by collection TW 595 which contains several specimens probably belonging to the ammonite Phlyseogrammoceras. This identification is based on the presence of fasciculate ribbing, umbilical tubercles, and a sharp umbilical edge. The same species preserved in identical matrix was collected by Arthur Grantz 2.95 miles N. 9 deg. E. of the mouth of Sheep Creek in the Talkeetna Mountains. The Bajocian stage is represented by most of the remaining collections. Of these, collections RAL 44, TW 585 and 581, and SGW 62-8, SGW 63-1, SGW 63-4, and SGW 63-16 contain ammonites that in the Cook Inlet area occur in the upper part of the siltstone member directly beneath the Gaikema sandstone member of the Tuxedni formation. I consider that the beds containing these fossils correspond to the European zone of Otoites sauzei. In addition, collections SGW 7A, 60, 62-18, 62-23, 62-24, 62-25 and 63-3 contain ammonites that in the Cook Inlet area occur in the middle siltstone member between the Gaikema sandstone member and the Cynthia Falls sandstone member of the Tuxedni formation. I am correlating this middle siltstone member with the European zone of Stephanoceras humphriesianum because of the abundance of Normannites and presence of Teloceras. Certain collections such as SGW 13A, 61, and 235 cannot be definitely placed but are probably Bajocian. Collections RAL 65 and 67 contain well preserved specimens of Cranocephalites, which genus is probably of Bathonian age. I have prepared a Prof. Paper on the ammonite fauna which will present considerable evidence favoring a Bathonian age. My conclusions have received support recently from Calloman (1959, Geol. Mag. Vol. 96, no. 6, p. 505-513) based on his studies in East Greenland. Collections RAL 24 and 48 contain ammonites of early to middle Callovian age. The fossils are listed below by localities. These not definitely identified specifically are either immature forms or represent new species. These new species will be described by me in a Prof. Paper that is more than half completed. As I am now describing the Bajocian ammonites from the Cook Inlet area and the Talkeetna Mountains, I would like very much to have locality data on these ammonites and in particular on collections from localities SGW 62-18, RAL 14 and TW 591. Also, I would like permission from you to illustrate certain specimens that are better preserved or show certain features better than the specimens in the Survey collections. Please let me know if this is permissible and whether such specimens would remain here in Washington or be returned to your collections at UCLA. If you want them returned, we would like to have you assign them catalog numbers to appear in the final publication. |