1897.] DRAKE — THE GEOLOGY OF INDIAN TERRITORY. 383 



groups running through the entire area. The following descriptions 

 of local developments and their general connections will give a 

 better idea of the stratigraphy and lithology. 



About five miles northwest of Calvin, along Sandy creek, the 

 strata consist of massive, friable, yellowish sandstones interstratified 

 with gray and yellowish argillaceous compact sand. About a mile 

 farther west, along the Calvin-Wewoka road, there are some sand- 

 stone beds exposed which are practically like the above, but are 

 highly fossiliferous and apparently belong either to the Upper 

 Coal Measures, or the Lower Permian. These sandstones are so 

 friable, thick and extensive that the country for fifteen miles or 

 more to the northwest of Calvin is covered by deep loose sand 

 from the disintegration of the rock. Railway cuts three to four 

 miles northwest of Holdenville show the strata at that place to be 

 principally gray arenaceous clays with occasional reddish bands 

 and streaks which carry numerous yellowish, ferruginous, calcareous 

 clay nodules. There is some lenticular interbedded sandstone 

 which is hard and has a clear quartzitic appearance. Similar clay 

 shales and thin interstratified sandstone beds, aggregating a thick- 

 ness of six hundred feet or more, are the outcropping strata for 

 several miles on either side of Holdejiville. It seems probable that 

 this group is the base of the Permian and is the stratigraphic equiv- 

 alent of about five hundred feet of similar strata outcropping both 

 east and west of McDermitt. Farther to the north it thins 

 quite rapidly or is replaced by sandstone beds until west of Kelley- 

 ville and northwest of Skiatook it is but one hundred to two hun- 

 dred feet thick and contains no red clays. At the top of this 

 group, along the Calvin-Wewoka section, there is a limestone from 

 three to four feet thick. This limestone outcrops about two miles 

 southwest of Wewoka, where it shows a weathered surface of gray 

 and yellowish color, is very friable, and in places is quite arena- 

 ceous. About *a mile farther west this limestone is overlain by a 

 conglomerate and sandstone bed aggregating two hundred and fifty 

 feet or more in thickness. The larger part of this bed at this 

 locality is conglomerate, composed of rather angular light-colored 

 chert pebbles two to three millimetres in diameter, imbedded in a 

 sand matrix. Occasional well-rounded quartz pebbles, about five 

 millimetres in diameter, also occur in the conglomerate. This 

 conglomerate has the same lithologic characteristics of the con- 

 glomerate beds that extend from northern to central Texas through 



