1895. ] NEW YORK ACADEMY OF SCIENCES. 59 
north, and southeast to almost south, at from 20 to 80 degrees. 
Prof. R. T. Hill devoted much labor to the investigation of this 
gorge, but was unable to determine the structure, which is cer- 
tainly more than ordinarily perplexing. A sharply defined fault 
is shown in the long side cutting just beyond where the road 
first reaches the river, and another at the gravel pits, say half a 
mile further south. The ridge has a southeastward trend and 
can be traced for a considerable distance even by one riding on 
a railroad train; but it is cut off abruptly toward the southern 
border of Indian Territory, where one comes to the lower beds 
of the Cretaceous. 
Prof. Hill’s collections in the Wichita gorge proved the occur- 
rence there of palaeozoic rocks from Trenton to Oriskany. Car- 
boniferous beds are found again on the southerly side of the 
mountains, and near Ardmore is an asphalt deposit, which 
promises to be of some economic importance. 
Direct tracing of the Coal measures from Arkansas into Texas 
seems hardly possible, for the Cretaceous overlap at the foot of 
the Ouachita mountains extends for two-thirds of the southern 
line between Texas and Indian Territory. Prof. Hill’s ‘“ Red 
Beds” are shown by him to be continuous from Texas into the 
Territory around the westerly end of the Arbuckle mountains. 
But those beds can hardly prove very useful. The writer in 
company with Prof. Cummins, of the Texas Survey, visited the 
region whence Permian fossils have been obtained, about 150 
miles northwest from Fort Worth. If the beds in that region 
are the same with the ‘‘ Red Beds” at Purcell and southward in 
Indian Territory, one will need fossils to prove the identity, for 
the lithological characters are wholly dissimilar ; still the inter- 
val between the localities is considerable and change in charac- 
ters may be gradual. 
The limestones of Indian Territory afford the best means of 
correlation at present. The Bend stage in Texas, as described 
by Cummins, is near the base of the Upper Carboniferous ; its 
special fauna is found in the limestones near Dougherty ; the 
limestones of the Choctaw nation occupy a similar place in the 
section. The writer feels justified in regarding the Choctaw, 
Dougherty and Bend limestones at practically the same horizon ; 
and in concluding that, during the early portion of the Upper 
Carboniferous, like conditions prevailed from Arkansas to cen- 
tral Texas. To work out the upper portion of the section in 
central Indian Territory will prove tedious, as the region has 
been base-leveled and the rolling prairie shows few exposures. 
Messrs. Hill, Winslow, Griswold and Chance have studied the 
Ouachita mountain system of western Arkansas and the Indian 
