19

COAL.

There are in Texas three distinct coal fields-the Central or Bituminous, the Nueces or Semi-Bituminous, and the Lignitic.

The Central Coal Field is a continuation of the Missourian, or fourth coal basin of the United States, of which it is the southern extremity. Its approximate boundary is a line from the eastern corner of Montague County, running southwest from Red River just west of Decatur and Weatherford, through the southeastern corner of Palo Pinto County, and west of the town of Commanche to the eastern line of Brown County. From this point it runs more directly south, passing through Lampasas into Burnet County, where the formation has its most southern exposure so far as at present determined. On the west it appears again in Kimble and Mason counties, and the line running north passes through Menard, Concho, Runnels, Taylor, Callahan, Shackelford, and Throckmorton counties. through the southeastern portions of Archer and Clay to the mouth of the Little Witchita. This field covers in whole or in part some twenty-five counties, and has an area of not less than twelve thousand square miles. Its eastern border is overlaid by the rocks of the Cretaceous formation, while the Permian beds rest upon it on the west.

The section made by Prof. Cummins shows the thickness of the formation to be not less than 2000 feet, with nine seams of coal, of which two at least, and probably three, are workable. The work which has been done on the central portion of this field is fully detailed by Prof. Cummins.

Prof. Chas. Ashburner, who made a partial examination of these coals in 1879, saw no coal stratum lower than that found four and a half miles northwest of Crystal Falls, in Stephens County, which he named the Brazos Coal Bed. He says; "The coal strata proper are 85 feet thick, and are included between an upper sandstone and conglomerate and a lower gray limestone. The coal strata contains two beds of workable thickness. The upper, named Belknap, ranges from 2½ to 4 feet, and the lower, named Brazos, from 4 to 6 feet in thickness. The coals are high in ash and sulphur, but have never been thoroughly tested. The Brazos bed underlies a great area, and will no doubt prove to be a valuable commercial coal in some localities."

These two beds may be still higher than those reached by Prof. Cummins, or they may belong to his seams number 7 and 8. His examination will soon determine this fact.

Specimens of these coals will be subjected to analysis at once in order to ascertain their true value.

The Nueces Coal Field.—The Neuces or semi-bituminous coal field, as described by Mr. Owen, includes parts of Webb, Dimmit, Zavala, and Maverick counties, and has an area of thirty-seven hundred square miles, and the northern boundary not yet determined.

It contains two workable seams of coal and locally at least three. These differ somewhat in character, the lower is a semi-bituminous coal, probably of cretaceous age, which, so far as it has been examined, gives promise of being a very good fuel. It is being worked north of Eagle Pass at the Hertz mines.

The other bed, which is now being worked at San Tomas, is possibly of the Laramie group but can hardly be older. It is really somewhat lignitic, although, as Mr. Owen states, quite different from the lignites of our Tertiary coal field.

Another variety which is also found in some quantity in this coal field is Albertite. Specimens of this were collected by Dr. Geo. G. Shumard, in 1860-61, but I find no mention of it in his manuscript. This seam is northeast of the San Tomas exposure and will prove valuable.