384 DRAKE — THE GEOLOGY OF INDIAX TERRITORY. [Sept. 3, 



the Cisco division of the Coal Measures of Texas. ^ The outcrop 

 of this conglomerate and sandstone bed forms a belt ten miles 

 wide that extends nearly north and south through the centre of the 

 Seminole Nation. Farther northward the conglomerate gradually 

 disappears and the beds thicken by addition of other sandstone 

 beds until it is apparently five hundred feet thick and outcrops in a 

 belt about twenty miles wide. This belt lies twelve miles east of 

 Arlington, two miles west of Kelleyville, and about eight or ten 

 miles east of Pawhuska. 



The sandstones of this belt are so friable that the country is cov- 

 ered by loose sand derived from the disintegrated rock. About four- 

 teen miles east of Arlington the group contains a bed of light-gray 

 sandy clay shale, seventy- five or one hundred feet thick, which 

 contains some limonite nodules and one thin stratum of rich hema- 

 tite. There are also two strata of limestone, each one or two feet 

 thick, which occur near the base and top of the shales respectively. 



Proceeding upward and westward across this sandstone and con- 

 •glomerate group of beds from about a mile west of Kelleyville to 

 about eight miles west of that place, the strata are found to be 

 mainly sandstones, which are massive, rather ferruginous, friable 

 and weather into rough irregular shapes. The rapid disintegration 

 of the rock covers the ground with deep loose sand. About nine 

 miles west of Kelleyville the sandstone is slightly shaly in places 

 and some red sandy clays are interstratified with the sandstone 

 beds. The dip of these beds is about fifty feet per mile to the 

 westward, or a little north Of westward. The thin interbedded 

 shales and clays and alternating harder sandstone beds allow only 

 very slight escarpments to be formed. On top of these sandstones 

 there is about one hundred feet of gray sandy clay shale and some 

 interstratified shaly sandstone. Over the outcrop of this shale 

 there is not much loose sand and the bed is marked by little prai- 

 ries. The dip of the strata here is about twenty to twenty-five 

 feet per mile to the westward. Ten to eleven miles west of Kelley- 

 ville the rocks are massive cross-bedded sandstones ; in these 

 the bedding planes are curved surfaces separating their lenticular 

 and wedge-shaped layers. It is interstratified with a little bluish 

 argillaceous sand, red clays and gray argillaceous sandy shale. For 

 the next five or six miles to the westward the strata lie practically 

 horizontal, then farther west to the top of the sandstone group, 



^Geol. Surv. Texas, Fourth An. Rep., 1892, pp.372, 445; Geol. Surv. 

 Texas, Second An. Rep., 1890, pp. 362, 495, 509, and PL xvi. 



