Area in Louisiana and Eastern Texas. 



65 



Mississippian 

 Caney shale 



0k-l,500c 



Jackf ork sandstone .... 01-6,600™ 



Stanley shale 0i-6,100n 



Hot Springs sandstone 0o-200c 



Devonian : 



Arkansas novaculite (upper 

 part may possibly be Car- 

 boniferous) 0o-950o 



Silurian : 



Missouri Mountain slate. . . .0o-300o 



Blaylock sandstone 0o-l,500o 



Ordovician : 



Polk Creek shale. 



,0o-400p 



Bigfork chert 700o 



Womble shale 250o-l,000o 



Blakely sandstone 



Exposed in Ouachita region in Ok- 

 lahoma ; absent in Arkansas. 



Exposed in Ouachita region in Ok- 

 lahoma and in Arkansas Valley 

 and Ouachita region in Arkan- 

 sas; absent at one locality in 

 Oklahoma. 



Exposed in Ouachita region in Ok- 

 lahoma and Arkansas; absent at 

 one locality in Oklahoma. 



Exposed in places at and near Hot 

 Springs, Ark., but absent at 

 most places in Arkansas; not 

 present in Oklahoma. 



Exposed in Ouachita region in Ok- 

 lahoma and Arkansas ; absent at 

 few places in Arkansas. 



Exposed in Ouachita region in Ok- 

 lahoma and Arkansas. 



Exposed in southern part of the 

 Ouachita region in Oklahoma 

 and Arkansas; absent in north- 

 ern part of this region in both 

 States. 



Exposed in Ouachita region in Ok- 

 lahoma and Arkansas; absent 

 at few localities. 



Exposed in Ouachita region in Ok- 

 lahoma and Arkansas. 



Exposed in Ouachita region in Ar- 

 kansas; also present in Ouachita 

 region in Oklahoma.^ 



, 0o-500o Exposed in Ouachita region in Ar- 

 kansas; present in Ouachita 

 region in McCurtain Co., Okla.i 



275. f Taff, J A., and Adams, G. I., op. cit., p. 274. g Collier, A. J., The 

 Arkansas coal field, U. S. Geol. Survey, Bull. 326, p. 12, 1907. ^ Taff, J. A 

 Grahamite deposits of southeastern Oklahoma, U. S. Geol, Survey, Bull 

 380, p. 289, 1909. i Measured by writer in Yell County, Arkansas. J Wallis, 

 B. F., The geology and economic value of the Wapanucka limestone of Okla 

 homa, Oklahoma Geol. Survey, Bull. 23, pp. 30, 42, 67, 1915. k Wallis, B. F. 

 op. cit., p. 67. 1 Girty, G. H., The fauna of the Caney shale of Oklahoma 

 U. S. Geol. Survey, Bull. 377, p. 6, 1909; Wallis, B. F., op. cit., p. 27 

 m Purdue, A. H., The slates of Arkansas, Arkansas Geol. Survey, p. 48, 1909 

 i^Taff, J. A., U. S. Geol. Survey, Geol. Atlas, Atoka folio (No. 79), colum 

 nar section sheet 2, 1902. o Measured by A. H. Purdue and writer in Ar 

 kansas. p Ulrich, E. O., Eevision of the Paleozoic systems, Geol. Soc. Amer 

 Bull,, vol. 22, p. 677, 1911. Q c, W. lioness, structural features of the south 

 ern Ouachita Mountains, Oklahoma (abstract) : Geol. Soc. America, Bull, 

 vol. 31, No. 1, p. 121, March, 1920. 



