J 88 1. li> Trans. N. Y.Ac. Sci. 



beds, having a general northeast and southwest direction. In Wil- 

 barger County the gravel drift is in great quantity, and boulders from 

 three to seven inches in diameter occur. In places, and having a north- 

 east and southwest bearing, heavy deposits or Hnes of gravel and 

 boulders attract attention, appearing as though a great flow towards 

 the southeast had met obstructions along its course, the great incline 

 of this region being directed toward the southeast. Beyond Pease 

 Riv^er the gravel drift lessens, but the large boulders are occasionally 

 seen as far west as the gypsum hills. Not far north from the centre of 

 Hardeman County I again found the Haskell County copper bed, the 

 accompanying sandstones being thin and much mixed with gypsum. 

 The copper bed reaches higher than the surrounding country, except 

 the gypsum hills to the west. From this high locality of the copper, 

 known as Prairie-dog Mounds, the country inclines on one side north- 

 ward to a creek emptying into Red River, and on the other side south- 

 ward to the Pease River. South of these mounds, where only here and 

 there patches of the bed are preserved in the midst of a general erosion, 

 I found the largest mass of copper ore thus far discovered, consisting 

 of an aggregation of cuprified wood, resembling the trunk of a tree, 

 more than one foot in diameter. 



Beyond Red River the bed continues to the vicinity of the Salt 

 Fork of Red River, distant but little over 20 mil*s from ihe 

 Wichita Mountains of the Indian Territory. The bed probably con- 

 tinues nearly to the western end of these mountains, and here must be 

 found the true centre of elevation and the origin of the gravel drift. 

 The Haskell County copper bed was also traced south to the Wichita 

 River, thus establishing its continuity from the southern portion of 

 Haskell County, through Knox and Hardeman Counties, into the Indian 

 Territory, a length of more than 100 miles. Subseqaently, the northern 

 end of the bed was found a short distance from the western end of the 

 Wichita Mountains, on the south side of the range. The copper for- 

 mations of Archer and Wichita Counties continue through Clay County 

 to the Red River boundary of the Indian Territory. The gravel drift 

 does not extend to the north of the Wichita Mountains, but a limestone 

 district occurs about 20 miles in width, that reaches probably as far out 

 to the north, from the Wichita Range, the course of the latter being 

 east and west. This limestone area may be called mountainous, is 

 much disturbed and tilted, and is similar in appearance to the metalli- 

 ferous limestone formation of Mexico. The Wichita Mountains are 

 mainly made up of porphyries, trachytes and basalt, and appear to be 

 two parallel ranges with transverse ranges and small valleys between. 

 About 12 miles west of Fort Sill an extensive body of hornblende slate 

 makes its appearance between the two main ranges. The drift from 

 the mountains extends to the south and southeast. It is found as far 

 west as the Haskell County copper bed, and as far east as the Archer 

 County copper bed is known. The river channels of that section of the 

 country have been formed since this drift period. The development of 

 the Wichita Mountains seems to have marked the close of a period of 

 uplift and simultaneous erosion. 



