THE 
AMERICAN GEOLOGIST 
Vou, IX. JUNK, 1892. No. 6 
THE DOUBLE MOUNTAIN SECTION. 
(Puare VIII) 
By E. T. DumBLE and W. F. Cummins, Austin, Tex. 
In pursuance of the work of the survey, in making a section 
across the Permian strata of Texas, we left Abilene early in Octo- 
ber, 1889, and traveled north and a little east to the contact of 
the Carboniferous and Permian, on the Clear fork of the Brazos 
in Throckmorton county. From here we turned directly west 
crossing the Permian beds to the Double mountains, where we 
expected to find the contact between the underlying Permian and 
any Triassic or Jurassic beds which might occur, and the overly- 
ing Cretaceous. While we found no Jurassic, the section of these 
mountains is nevertheless of interest, since it is the most northern 
point in this northwestern portion of the state at which the beds 
of the Lower Cretaceous are exposed, and the most easterly ex- 
posure of the Trias which we have been able to recognize. 
The Double mountains are situated in the southwestern corner 
of Stonewall county between the Double Mountain fork and the 
Salt fork of the Brazos, just south of the thirty-third parallel of 
latitude, and in longitude 100° 25’. They consist in reality of 
three peaks or buttes, one of which, however, is so situated with 
reference to the other two as to be invisible on the approach from 
the southwest in consequence of which they have received their 
name. ‘T'wo of the peaks present the usual butte structure so 
characteristic of the Cretaceous hills, when capped with the Ca- 
