GENERAL CHARACTER AND CORRELATION 709 



include Karnic forms has been made by Mojsisovics, 42 who said: "The 

 same conclusion [of Karnic age] holds for Aulacoceras carlottense, since 

 the genus Aulacoceras until now has been known only in the Karnic. The 

 fragment of a coil figured as Acrochordioceras (?) carlottense may belong 

 to a Juvavites." 



The same horizon is possibly present at the north end of "Vancouver 

 Island, where, according to Dawson, 43 the section is very similar to that 

 in the Queen Charlotte Islands, and includes a massive limestone, possibly 

 1,000 feet thick, underlain by volcanic rocks and overlain by "flaggy 

 limestones interbedded with calcareous argillites, black flinty argillites, 

 and felsites." This limestone, and also the supposedly equivalent lime- 

 stone of the Queen Charlotte Islands, is part of the thick and heterogene- 

 ous aggregate of rocks that has been described as the Vancouver series. 



Coral-reef horizon. — An Upper Triassic limestone, occurring on Ili- 

 amna Lake, has yielded a fauna, composed chiefly of corals, which has 

 not been recognized with certainty elsewhere in Alaska and which, accord- 

 ing to Prof. James Perrin Smith, is of Lower Noric age and is to be cor- 

 related 44 with the coral-reef zone in the upper part of the Hosselkus lime- 

 stone of California and in the Blue Mountains of Oregon and Avith the 

 Zlambach fauna of the Alps. The position of this limestone in the Chit- 

 ina Valley section is above the Halobia zone of the Chitistone limestone 

 and below the Pseudomonotis zone of the McCarthy formation. It may 

 be represented by the thin-bedded JSTizina limestone or by beds that have 

 been cut out by an unconformity at the base of the McCarthy formation. 



This limestone may be present also on the west coast of Cook Inlet and 

 on Gravina Island, in southeastern Alaska, but at neither of these locali- 

 ties has it been recognized with certainty. 



The Lower JSToric coral-reef horizon is possibly represented in British 

 Columbia (see figure 1) by the Sutton limestone 45 of Cowichan Lake, 

 Vancouver Island. The fauna of the Sutton limestone has been described 

 by Clapp and Shinier, 46 who referred it to the lower part of the Lower 

 Jurassic on the ground that its species are more primitive than certain 



42 Edmund von Mojsisovics : Beitriige zur Kenntniss der obertriadischen Cephalopoden- 

 Faunen des Himalaya. Denkschriften del" kaiserlichen Akademie der Wissenschaften. 

 Wein, Bd. lxiii, 1S96, p. 697. 



43 George M. Dawson : Report on a geological examination of the northern part of Van- 

 couver Island and adjacent coasts. Geological and Natural History Survey of Canada, 

 vol. ii, new series, 1886, pp. 9B, GOB, 76B, SOB, 91B. 



"James Perrin Smith: The occurrence of coral reefs in the Triassic of North Amer- 

 ica. Am. Jour. Sci., vol. 33 (4th series), 1012, pp. 92-96. 



45 Charles H. Clapp : Southern Vancouver Island. Geol. Survey of Canada, Memoir 

 No. 13 (1121), 1012, pp. 36, 61-60. 



4 s C. II. Clapp and H. W. Shimer : The Sutton Jurassic of the Vancouver group, Van- 

 couver Island. Proc. Boston Soc. Nat. Hist, vol. 34, No. 12, 1911, pp. 425-438, pis. 40-42. 



