260 ('. .1. Reeds— Hunton Formation of Oklahoma. 



shale was intercalated in this member. Its presence indicates 

 that the muddy water conditions of the Sylvan were resinned 

 at this time and place. The presence of limestone lentils at 

 Other localities foreshadows the deposition of the overlying 

 white glauconitic limestone or middle member. 



G-lauconitic member. — This member was found in all of the 

 numerous exposures examined except one near Sheep creek 

 where the pink-crinoidal member rests on the oolitic member. 

 The 35 sections made across the Hunton show that it varies in 

 thickness from to 25 feet. It is a white to gray, granular to 

 crystalline, generally massive bedded limestone, disseminated 

 with green glauconitic grains. The presence of the green 

 glauconite, white color and granularity readily distinguish it 

 from the oolitic and pink-crinoidal members, between which it 

 is intercalated. i 



PinTc-crinoidal member. — This limestone constitutes the 

 uppermost member of the Chiinneyhill formation. Typical 

 exposures are to be found in the Lawrence and Hunton anti- 

 clines and Franks syncline along the northeast border of the 

 mountains between Lawrence and Bromide. The exposures in 

 the vicinity of Dougherty in the west central part of the 

 mountains are not so characteristic. Typically the member is 

 a thin bedded, compact earthy to crystalline limestone contain- 

 ing numerous crinoidal fragments which have been stained 

 pink by infiltrated iron and manganese. The member varies 

 in thickness from to 39 feet, with an average thickness of 

 approximately 15 feet. This variation in thickness is accounted 

 for chiefly by the differential erosion which affected the mem- 

 ber previous to the deposition of the Henryhouse shale, and, 

 in places where it has been completely carried away, by a sec- 

 ond period of erosion, the one just previous to the deposition 

 of the Haragan shale. 



Fauna. — The fauna of the Chimneyhill limestone is roughly 

 equivalent to that of the Ohio Clinton and Erassfield forma- 

 tions east of the Cincinnati axis in Ohio and Kentucky. It is 

 still more closely related, however, to the Ohio Clinton west of 

 this axis in Indiana, southern Illinois, Kentucky and Tennes- 

 see. In fact, as at present understood, the Chimneyhill was 

 deposited in the same marine waters but near the opposite 

 shore of a rather restricted geographical province, the Indiana 

 basin.* It would thus be expected that the faunas are some- 

 what alike but not necessarily the same in every particular. 

 The names and stratigraphic range of the characteristic species 

 of the Chimneyhill formation are as follows : 



* Schuchert, C, Paleogeography of North America, Bull. Geol. Soc. Am., 

 vol. xx, pp. 532-538, pi. 64. 



