34 



CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



from western North America. Owing to the well known in- 

 timate connection between the Upper Trias of California and 

 that of southern Europe — the region which Neumayr years ago 

 called the " central Mediterranean," and for which the name 

 " Thetys " was proposed by Suess in 1894 — we might expect on 

 purely a priori grounds to find a certain resemblance in the 

 character of the vertebrate faunas of the two regions.' 



The scant evidence thus far obtained, however, at least as 

 regards the fishes, fails to justify any such expectation. From 

 the Lower Trias of Idaho have been described a single detached 

 dermal spine, apparently belonging to Aster acanthus,^ and a 

 few fragmentary remains of Crossopterygii, which are possibly 

 late survivals of Paleozoic families (Rhizodontidse and Osteol- 

 epidae).' Elasmobranchs and effete Crossopterygii persist even 

 as late as the Upper Trias of Shasta county, California, where re- 

 mains of Hybodus, Acrodus, Holoptychius and Xenestes have 

 been brought to light, whose number, however, all told, makes 

 an inconspicuous showing.* 



Yet another sprinkling of ichthyic indications is known from 

 the Red Beds of supposed Triassic age (Shinarump group) in 

 southwestern Colorado and in the Kanab Canyon region of Utah 

 and Arizona. Little has been published on the fossil vertebrate 

 remains from this section,^ but, so far as the fishes are concerned, 

 it is clear that they display no intimate relations with those of 

 the Atlantic border Trias. On the contrary, the general aspect 



' In regard to the invertebrate faunas, Dr. James Perrin Smith has the following: 



*' The most interesting fact brought out by a comparison of the Upper Trias of 

 California with that of India and the Alpine Mediterranean region is its near rela- 

 tionship with the latter, most genera and many species being common to the two 

 regions. . . . This relationship of the Californian to the European faunas per- 

 sists until after the middle of the Jurassic formation, when the Boreal fauna comes 

 in." — Journ. Geol., 1898, vi, p. 786. 



' This is described under the name of Cosmacanthus by H. M. Evans, in Bull. Dept. 

 Geol. Univ. of Calif. , 1904, iii, p. 397. 



' Goddard, M., Fish Remains from the Marine Lower Trias of Aspen Ridge, Idaho. 

 Bull. Dept. Geol. Univ. of Calif., 1907, v, p. 145. 



' Wemple. E. M.. New Cestraciont teeth from the West American Triassic. Bull. 

 Geol. Dept. Univ. of Calif., 1906, v, no. 4, p. 73.— Jordan, D. S., The Fossil Fishes 

 of California. Ibid., 1907, v, no. 7, pp. 95-144. 



•The chief literary references are collected by Dr. Whitman Cross in his article 

 on " The Triassic Portion of the Shinarump Group, Powell," to be found in the 

 Journal of Geology, 1908, xvi, pp. 97-123. See also the joint paper by the same 

 author and E. Howe, entitled " Red Beds of Southwestern Colorado and their Cor- 

 relation." Bull. Geol. Soc. Am., 1905, xvi, pp. 447-486. 



