Wichita Mountains and Arbuckle Hills. — Vaughan. 45 
♦ 
geological survey and published a report in the first (second) 
annual report of that institution, pp. 319-328. This contribu- 
tion gives us much data on the geography of the mountain 
range, additional notes on the rocks constituting it, 'and Silu- 
rian fossils were found in the limestone hills on both sides of 
the plutonic axis. No positive evidence further than the Silu- 
rian strata are much tilted and the Permian slightly tilted, is 
presented bearing upon the time of the orogenic movements. 
The last contribution is by Mr. R. T. Hill.* He gives some 
notes on the general topographic features of the mountains, 
and their constituent rocks. He states: 
The composition of the Wichitas is unlike that of any area of the 
southwest, and, so far as I could see, presents no structural resemb- 
lance either to the basin-surrounded mountains of the Trans-Pecos, or 
the early Paleozoic buttes and denuded folds of the Central Texas re- 
gion. Their age is not determined. They are certainly post-Silurian 
and the Red beds have in part participated in the movements but the 
eruptives may be post-Cretaceous or even later. The apparent absence 
of the Lower and Upper Cretaceous in the composition of the Wichitas 
is especially noticeable." 
General Topographic Features. 
As one goes southward from Arapaho, he sees several 
mountain masses, thirty or forty miles distant projecting above 
the horizon line. As the mountains are approached, it is seen 
that north of the mountains there are rounded hills and that 
north of these hills there is a southward facing escarpment a 
hundred feet or more in hight. As my reconnoissance was 
mostly on the north side of the mountains, I can say but little, 
that is based on personal observation, concerning the south 
side. The main axis of the mountains trends slightly north of 
west, running from about Ft. Sill in the Comanche and Kiowa 
reservation a little north of Mangum in Greer county. They 
are about 120 miles long. Varying in distance from two or 
three to five or six miles north of the axis, and separated from 
it by a level, flat, grass-covered valley, are hog-backs of lime- 
stone, rising several hundred feet above the valley. Ten miles 
or more north of these hills, and separated from them by a 
valley is a southward facing escarpment, above which is the 
*"Notes on a Reconnoissance of the Ouachita Mountain System in 
Indian Territory'', (Amer. Jour. Sci, vol. XLII, Aug. 1891,'pp. 122- 
123) contain a brief description of the Wichita mountains. 
