MISSISSIPPIAN ROCKS OF NORTHEASTERN OKLAHOMA 621 



member, the Wedington, which reaches a thickness of 40 feet. It 

 thins out to the west and disappears about the middle of the 

 quadrangle. In the Pryor quadrangle, the Fayetteville has the 

 same general characteristics as to the south in the Muskogee 

 quadrangle. The limestones thicken somewhat to the north, and 

 are more persistent while the formation as a whole thins consider- 

 ably. On the bluff of Grand River southeast of Choteau, the 

 thickness is 90 feet. The basal 18 feet are composed of alternating 

 layers of black shale and blue, dense limestone averaging about 

 6 inches in thickness. The limestone has a conchoidal fracture, 

 is non-fossiliferous and weathers to a very light gray color. About 

 the middle of the formation is a bed of limestone 12 feet thick, of 

 which some layers are composed in large part of the shells of Pro- 

 ductus pileiformis and P. cestriensis. This limestone is persistent 

 for some miles to the north. So great a thickness has not been 

 observed elsewhere, but this may be due to the poorer exposures. 



The following species were collected from the limestones of the 

 Fayetteville about 4 miles southeast of Ft. Gibson in the Muskogee 

 quadrangle: Lingulidiscina sp., Productella cf. hirsutiformis Wal- 

 cott, Productus sp., P. pileiformis McChesney, P. cestriensis 

 Worthen, P. cf. infiatus var. coloradoensis Girty(?), P. cf. sub- 

 sulcatus Girty, Moorefieldella eurekensis Walcott, Spirifer arkan- 

 sanus Girty, S. increhescens Hall, Martinia glabra Martin(?), 

 Spiriferina sp., Camarophoria sp., Reticularia setigera Hall, Seminula 

 siibquadrata Hall, and Eumetria marcyi Shumard. The following 

 additional species are listed by Taff in the Muskogee folio: Septo- 

 pora cestriensis Prout, Archimedes compactus Ulrich, A. communis 

 Ulrich, A. intermedins Ulrich, A. swallovanus Hall, Polypora 

 corticosa Ulrich, Spiriferina spinosa N. and P. 



To the north, in the southeastern corner of the Vinita quad- 

 rangle, it is necessary to consider the Fayetteville and Pitkin 

 horizons together. The section of the Mississippian rocks above 

 the Boone chert in this vicinity is made up of four limestones and 

 three shales. The lowest limestone is the unnamed hmestone at 

 the top of the Boone which has been considered. The topmost 

 limestone is about 15 feet thick, and is probably the Pitkin lime- 

 stone, although there is some doubt as to this correlation. The 



