368 GEOLOGY OF NORTHWESTERN TEXAS. 



with like beds in other localities. The provisional subdivisions are shown in 

 Plate VI, page 361, in this Report. 



The Carboniferous area of Texas is an irregular belt of country stretching 

 from Red River on the north southward to and below the Colorado, a distance 

 of over two hundred miles, and having an average breadth of not more than 

 seventy-five miles, with its longer axis approximately in the line of the strike 

 of the formation. 



The Carboniferous formation in Texas is overlaid on the eastward by the 

 Trinity Sands along the entire eastern border. A line representing the east- 

 ern contact between the two formations would begin at a point on Red River 

 near the northeastern corner of Montague County. Thence passing through 

 Wise County, between Decatur and Bridgeport. Thence to a point on the 

 line of the Texas and Pacific Railway three miles east of Millsap. Thence 

 crossing the west branch of the Houston and Texas Central Railway at Car- 

 bon. Thence near the northwest corner of Comanche County. Thence by 

 a line almost parallel with the west line of Comanche and Hamilton counties, 

 but a few miles west of them, passing near Nix Postonice, in Lampasas 

 County, and reaching the Silurian a few miles south of that place. 



The Carboniferous is bounded on the south by the Silurian. A line be- 

 tween these two formations on the south would begin at a point a few miles 

 south of the town of Nix. Thence crossing the Colorado River a few miles 

 south of Bend, and crossing Cherokee Creek a few miles above its mouth, 

 and passing two miles south of the town of San Saba, and crossing the San 

 Saba River near the mouth of Brady's Creek. Thence up that creek to its 

 source. Thence westward to Kickapoo Creek in Concho County. At this place 

 the Carboniferous formation is overlaid on the westward by the Permian. 



The line between these two formations on the west would begin at a point 

 on Kickapoo Creek, m Concho County, about where the main road from 

 Brady to San Angelo crosses that creek. Thence down Kickapoo Creek to 

 its mouth. Thence passing a few miles east of the town of Ballinger. Thence 

 to Buffalo Gap. Thence crossing the Texas and Pacific Railway between 

 Abilene and Elmsdale. Thence down Dead Man's Creek east of Fort Phan- 

 tom Hill to the Clear Fork. Thence down that stream to a point opposite 

 the town of Throckmorton. Thence by a line passing west of that town to a 

 point on the Brazos River near the mouth of Spring Creek. Thence passing 

 near the southeast corner of Archer County, Buffalo Springs, and to Red 

 River near the mouth of Belknap Creek. 



The northern boundary in Texas is Red River. In giving these boundaries 

 it is not intended to say that a straight line drawn between any two given 

 points would represent the exact contact between the two formations, for such 

 would not be the case. In places along the eastern boundaries the Carbon- 



