lxxxii REPORTS OF GEOLOGISTS. 



REPORT OF MR W. F. CUMMINS. 



Austin, Texas, March 31, 1890. 

 Mr. E. T. Dumble, State Geologist: 



Dear Sir — Having received instructions to make as detailed a section as 

 the time would permit of the southern part of the Carboniferous formation 

 in Central Texas, I took the field at Lampasas on March 13, with Mr. C. C. 

 McCulloch, Jr., as assistant. The general route was west to the Colorado, 

 then south to the contact of the Carboniferous and Silurian near Cherokee 

 Creek, San Saba County. From that point we traveled north and west to 

 the town of San Saba, and thence, via Richland Springs, Milburn, Trickham, 

 and Waldrip, to Santa Anna. We then turned southwest to Brady, Camp 

 San Saba (McCulloch County), reaching San Angelo May 31. In making 

 the examination the greatest care was taken in the exact identification of 

 strata. Where there was a stratum which could be recognized with certainty, 

 it was traced from hill to hill until its exact relationship to the over and un- 

 derlying beds was determined. This was prevented by the drift in many 

 places, and therefore a continuous section could not be secured. Wherever 

 an exposure of sufficient extent was found, instrumental measurements were 

 made of dip, etc. ■ 



Having completed this, I received instructions to continue westward and 

 make a like investigation of the Permian area. I therefore, with my party, 

 began the work of exploring the Permian formation at its extreme southern 

 limit, which is a few miles south of San Angelo, in Tom Green County. The 

 boundary of the formation had not been definitely determined except at places 

 widely distant from each other along the eastern edge. I therefore under- 

 took to trace the eastern boundary of the beds, or the line of contact between 

 the Coal Measures and the Permian. I traveled down the main Concho River 

 to a point almost south of Bailinger and a few miles above the confluence 

 of the Concho and Colorado rivers. I then went to Bailinger, in Runnels 

 County, and thence by way of Buffalo Gap to Baird. Finding at Baird that 

 I was east of the contact between the two formations, which had been ob- 

 scured by the overlying Cretaceous to the south, I turned westward to Abi- 

 lene, in Taylor County. 



The line of contact between the Carboniferous and Permian is seven or 

 eight miles east of Abilene. At Abilene I was -joined by the State Geologist, 

 who accompanied the party to the Double Mountains. From Abilene we 

 turned northward to the Clear Fork of the Brazos River; we then went 

 down the river northeastward, being all of the time on the beds of the Per- 

 mian; and passing through old Fort Phantom Hill, we reached the road from 



