726 CHARLES S. PROSSER 



therefore in my opinion the Texas deposits must rather be 

 assigned to the Permo-Carboniferous. 1 



In 1 89 1 came Dr. C. A.White's description of "thirty-two 



species of invertebrates from the Texan Permian," 



of which four Cephalopods belonging to the family Ammo?ioidea 

 were recognized as new. It was stated that two of these types, 

 Waage?wceras Curnminsi and Popanoceras Walcotti, "are so generally 

 regarded as indicating the Mesozoic age of the strata containing 

 them that if they alone and without any statement of correlated 

 facts had been submitted to any paleontologist he would not have 

 been warranted in referring them to an earlier period than the 

 Trias if he had followed the usually accepted standard of refer- 

 ence." 2 



In conclusion Dr. White stated that " The evidence upon which 

 the Texan strata have been referred to the Permian is fuller than 

 that which has been adduced with regard to any other North 

 American strata that have been so referred. That is, the evi- 

 dence both of the vertebrate and invertebrate fossils is in favor 

 of such reference, and the difference in the character of the strata 

 from those of the underlying Coal-measures, although not great, 

 is conveniently distinguishable;" 3 while he was inclined to con- 

 sider the Texan Permian as of younger age than the Indian and 

 Sicilian strata containing the commingled Mesozoic and Carbon- 

 iferous forms which were described by Professors Waagen and 

 Gemmellaro. 



Waagen correlated the "Red sandstones and shales of Texas, 

 with many remains of Vertebrates, Amphibia and Reptilia and 

 Goniatites Baylorensis, Hyattoceras Cumminsi, Medlicottia Copei and 

 Popanoceras Walcotti" with the " Weissliegendes and marl slate" 

 which he put at the base of the magnesian limestone, that formed 

 the upper division of his Permian system. 4 



Marcou stated " It is certain that the Wichita division belongs 



I Mem. Acad. Imp. Sciences Si. Pelersbourg,Yll e Ser., t. XXXVII, No. 2, 1889, p. 93. 

 Also see the correlation of the Texas deposits as shown in Table C, p. 94. 



2 Bull U.S. Geol. Surv., No. 77, p. 31. * Ibid., p. 38. 



'•Mem. Geol. Surv. India, Palcz, India, ser. xiii, "Salt-Range Fossils," Vol. IV, 

 Pt. II, "Geological Results," 1891. Tabular View showing the relations of the Salt- 

 Range Upper- Palaeozoic strata to the deposits of other countries, op. p. 238. 



