beede: upper permian red beds. 123 



crassus Meek and Worthen, B. montfortianus Norwood and 



Pratten, B. f, Sedgwickia topekaensis Shumard, Pleiiro- 



phorus f, Clidophorus occidentalU Geinitz, Told' a f aub- 



scitiUa Meek andHayden, My alina permiana 8 wa,\\ow , Myalina 

 av>c III') ides Meek and Hayden, 31. perattenuata Meek and Hay- 

 den, GerviUia longa Geinitz, Aviculopecten occidentalis Shum- 

 ard, Syringopora f, Spirorb')^ /, Cy there nebrascensis 



Geinitz. 



On page 113 in the former paper and on page 13 of this 

 one, White states, concerning the upper limit of the Texas 

 Permian, that "Along the western boundary of the Texan 

 Permian, as it has been characterized in the preceding para- 

 graphs, a series of strata about 250 feet in maximum thickness, 

 now generally known as the gypsum-bearing beds and thought 

 by some geologists to be of Triassic age, rest conformably 

 upon the Permian. In general aspect, in a prevailing red- 

 dish color, and in general lithological character, except the 

 prevalence of gypsum in some of the layers, and the some- 

 what greater prevalence of clayey material, these overlying 

 beds resemble the Permian beds upon which they rest. With 

 only one known exception, these gypsum-bearing beds have 

 furnished no fossils. The exception referred to is the dis- 

 covery by Mr. Cummins in Hardeman county, in the upper 

 stratum of those beds, of a thin magnesian layer, containing 

 numerous casts of a species of Pleurophorus . This being 

 generally regarded as a characteristic genus among Permian 

 molluscan faunas, and also being a prevailing form in the 

 Permian strata beneath these gypsum-bearing beds, the ques- 

 tion is suggested whether the latter ought not to be regarded 

 as constituting an upper part of the Texan Permian. These 

 beds have yet furnished no fossils which can with propriety 

 be referred to the Trias, and it is questionable whether any 

 Triassic strata exist in Texas." 



In an article entitled "Report on the Geology of North- 

 western Texas," Prof. W. F. Cummins gives a resume of the 

 previous papers on the Permian and other formations of that 

 region, ^" some of which have been referred to above. His 

 discussion of the Permian is rather fuU,^^ giving twenty-four 



17. Sec. Ann. Rep. Qeol. Tex., pp. 359-553, 1901. 



18. Pages 394-424. 



