120 C. H. GORDON 



of the beds toward the north is evidently the result of differences 

 in the conditions of sedimentation. The character of this part of 

 the formation suggests very strongly its origin on a coastal plain, 

 or river delta, to the south and west of which lay the sea in which 

 were deposited the marine "Albany" sediments. The inter- 

 relations of the two kinds of sediments suggest oscillation of the 

 shoreline upon a relatively wide coastal plain. These changes 

 may be explained as the result of oscillation of the land surface or, 

 possibly better, by the slow but intermittent sinking of the coastal 

 region. 



As suggested by Case, 1 Beede, 2 and others, the materials of the 

 "Red Beds" were evidently derived from a land mass on the north, 

 of which the Wichita and Arbuckle mountains are the remnants. 

 The following quotation from Beede 's paper is especially pertinent: 



The Arbuckle and Wichita mountains are probably the source of much of the 

 red sediment in which they are partially buried, and the former mountains are 

 directly responsible for the eastern extension of these beds in central Oklahoma. 

 The extent to which the lighter colored sediments of Kansas and Texas are 

 replaced by red sediments in Oklahoma and near it represents in a rough way 

 the limits of the influence of these mountains on the deposits of the time by 

 the spread of their sediments. By the time the deposition of the light colored 

 sediments had ceased the conditions had become such that nearly all the sedi- 

 ments derived from the land surrounding the basin were red. 



FAUNAL RELATIONS 



In the course of the field work collections of fossils were made 

 at many localities, chiefly in the region occupied by the "Albany" 

 beds. At the close of this paper is given a list of the invertebrate 

 fossils obtained from the Albany and Wichita areas. The list 

 includes the collection made by the author, and those made several 

 years since by Mr. E. O. Ulrich. The localities are indicated on the 

 map by corresponding numbers. These remains indicate, accord- 

 ing to Dr. Girty, a marked identity in the invertebrate faunas of 

 the Albany and Wichita areas. In the collections several different 

 faunas can be discriminated. One of these has the brachiopod 



1 E. C. Case, Bulletin of the American Museum of Natural History, XXIII (1907), 

 659-64. 



2 J. WV Beede, Journal of Geology, XVII (1909), 714. 



