OKLAHOMA ACADEMY OF SCIENCE 91 



Holaster simplex, Ostrea carinata, Schloenhachia leonensis. 



The large Fucoids are characteristic of the Caddo formation. 



Shell beds replaced by iron are characteristic of the Bokchito 

 formation. 



Exogyra arictina is characteristic of the Bennington limestone. 



XV. PRELIMINARY NOTES ON A NEW GEOLOGIC 



MAP OF THE ARBUCKLE MOUNTAINS OF 



OKLAHOMA 



C. E. Decker 



From Department of Geology, University of Oklahoma 



In a preliminary report on the geology of the Arbuckle and 

 Wichita mountains, Joseph A. Taff in professional paper 31, U. S. 

 G. S., in 1904 published a geologic map with scale about 5.)<4 miles 

 per inch. Differentiation of formations was made then as follows: 



Pre-Cambrian Igneous rock 



Mid-Cambrian Reagan sandstone 



Cambro-Qrdovician Arbuckle limestone 



Ordovician . — Simpson formation 



Ordovician Viola limestone 



Silurian ^ Sylvan shale and Hunton limestone 



Devonian Woodford cheit 



Carboniferous Conglom.erates, sandstone & shale 



Carboniferous Permian "Red Beds" 



The Hunton formation was divided into three members. Of 

 these, the lower part of the lower member was correlated with 

 the Clinton of Ohio and St. Clair limestone of Arkansas, and the 

 upper part with the Niagaran. The middle m.ember is correlated 

 with the Helderbergian ox Nevv York and the upper member is 

 tentatively correlated with the Oriskany of New York and the 

 Camden chert of Tennessee. Thus the Hunton form.ation included 

 members belonging to two different periods. 



In i910 the same geologic map with minor changes was reprinted 

 to accompany Bulletin 3 of the Oklahoma Geological Survey. But 

 in connection with this map a number of new structural sections 

 were made by Chester Reeds, showing the major structural fea- 

 tures which he worked out in connection vvith his physiographic 

 studies of the mountains. In this text the Pennsylvanian rocks 

 southwest of the mountains are given the name of the Glenn for- 

 mation in a columnar section accompanying the report. 



In 1911 Chester A. Reeds, after extended faunal studies, pub- 

 lished an article in the American Journal of Science on the Hunton 

 formation of Oklahoma, and at this tim-^ he subdivided this forma- 



