GENERAL CHARACTER AND CORRELATION 705 



the species from Nevada and California which has been referred to 

 Daonella lommeli Wissman, and an undetermined species of Ceratites 

 (Gymnotoceras). Daonella lommeli Wissman is a European species 

 which is considered as characteristic of beds that are generally referred 

 to the Ladinic, and, according to most writers, are regarded as represent- 

 ing the uppermost division of the Muschelkalk, or Middle Triassic, al- 

 though they are sometimes regarded as constituting the lowest division of 

 the Upper Triassic. The fossils from Nevada that have sometimes been 

 considered as identical with Daonella lommeli are regarded 30 by Prof. 

 James Perrin Smith as constituting a distinct species, Daonella dubia 

 Gabb, and as belonging near the middle of the Middle Triassic. Gymno- 

 toceras is an ammonite which is supposed to be highly characteristic of 

 the Arctic type of Middle Triassic faunas. All known American species 

 of Gymnotoceras are characteristic of the Daonella dubia zone of the 

 Middle Triassic of Nevada. The Alaskan fossils are presumably to be 

 regarded as belonging in approximately the same position. 



The same horizon is probably represented by part of the Nicola series 

 of the Interior Plateau region of British Columbia (see figure 1). The 

 Nicola series 31 is a thick succession of volcanic rocks with some inter- 

 bedded limestones and argillites containing 32 Pentacrinus asteriscus (?), 

 Terebratula liumboldtensis, Spiriferina or Cyrtina, Myacites cf. Jiumbold- 

 tensis, Daonella cf. lommeli, Trigonodus, Cardita, and Panopea cf. 

 remondi. The Nicola series has been supposed to contain Pseudomonotis 

 subcirculwris, but this fossil does not occur in association with the others, 

 having been obtained 33 from an outlying area of argillites resting on 

 volcanic beds that were correlated with those of the Nicola series. 



It should be noted that Daonella lommeli has been reported from many 

 other localities in British Columbia. Since in most of these cases more 

 or less doubt has been expressed concerning the identification ; since the 

 Canadian fossil doubtfully referred to this species has never been de- 

 scribed or figured ; and since in nearly all cases the fossil has been listed 

 as occurring in close association with characteristic Upper Triassic forms, 

 the writer believes that the species may have been incorrectly identified, 

 and that it probably is Upper Triassic species of Halobia. There is as yet 



30 James Perrin Smith : The Middle Triassic marine invertebrate faunas of North 

 America. U. S. Geol. Survey, Prof. Paper S3, 1914, pp. 143-144. 



a George M. Dawson : Report on the area of the Kamloops map-sheet, British Colum- 

 bia. Geol. Survey of Canada, Ann. Rept. (new series), vol. vii, 1896, pp. 49B-62B, 112B- 

 146B. 



32 Idem., pp. 50B-51B (The crinoid and brachiopods were identified by Whiteaves, the 

 pelecypods by Hyatt. > 



33 George M. Dawson : Preliminary report on the physical and geological features of 

 the southern portion of the interior of British Columbia. Geol. Survey of Canada. Re- 

 port of progress for 1877-1878, pp. 66B-67B. 



LI — Bull. Geol. Soc. Am., Vol. 27, 1915 



