368 DRAKE — THE GEOLOGY OF INDIAN TERRITORY. [Sept. 3, 



SEC. 8. FEET. 



Sandstone lo 



Shale and thin beds of sandstone 8oo 



Sandstone lo 



Shale and thin beds of sandstone 8oo 



Sandstone lo 



Shale and thin beds of sandstone 2000 



The beds that appear to underlie these are those of Walker, 

 Blue and Jack Fork mountains. 



They are but little different lithologically from the beds above 

 them, but the shales are of a darker color, and in the western part 

 of the belt there is some limestone to break the usual monotony. 

 The main ridges of Walker, Blue and Jack Fork mountains have 

 sandstones from fifty to one hundred feet or more in thickness in 

 the southern part of the ridges. 



Sees. 10, II, 12 and 13, PI. VII, show the general character and 

 variation of the rocks on the south side of Fourche Melane valley 

 from a point south of Red Oak to a point south of Hartshorne. 

 Sec. 10 lies south of Red Oak. The limestone, calcareous sand- 

 stone and arenaceous limestone shown in this section were seen 

 southwest of Red Oak, but they probably extend farther to the 

 east. In this section the first sandstone bed south of Fourche 

 Melane is about one hundred feet thick, usually massive. Twenty 

 to thirty feet of arenaceous limestone and calcareous sandstone 

 occurs on the north side, or at the base of this sandstone bed. 

 The next ridge to the south is formed by two sandstones each 

 ten to fifty feet thick and separated by about fifty feet of clay shale. 

 This shale southwest of Red Oak is partly replaced by five to ten 

 feet of hard, rather nodular, blue limestone. On the north side of 

 the fourth sandstone — the third prominent ridge south of Fourche 

 Melane — there is more arenaceous limestone and calcareous sand- 

 stone. It is only five to ten feet thick at the places where it 

 was seen. Farther west or south of Ponola, Sec. 11 shows the 

 stratigraphy of the first ridge south of Fourche Melane. At this 

 place the strata dip south 50°. There is a hard, blue limestone, fif- 

 teen to twenty feet thick, on the south side of the ridge ; this lime- 

 stone is underlain by about one hundred and twenty-five feet of 

 sandstone, of which the upper fifty feet is ferruginous and fossili- 

 ferous, and the lower part is hard massive sandstone. This sand- 



