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EIO GRANDE COAL FIELDS OF TEXAS.
The lower limit in thickness occurs over a very small area; the average thickness
is about 2 feet. In this seam a binder occurs. The binder consists of two thin
seams of sand, and varies in thickness from half an inch to 2 inches. Between
the seams of sand is a thin coal seam about half an inch thick. Of this coal seam
where examined:
a. Upper 9-inch does not coke.
b. Nine inches just above binder coking. c. Binder.
d. BeJow binder, 9 inches, coal all coking. 1
3. Carbonaceous shale T 1 to 3 in.
2. Fire clay 2 ft. a
1. Sandstone.
This section of the coal corresponds to Nos. 13 to 6, inclusive, of the
general section of the mountain.
Along the side of the mountain the usual dip is 5° to 7° (though it
may sometimes be more or less), and the strike is N. 35° to 50° E.
Above the soft sandstone (No. 11) are two other prominent sand-
stone ledges, about 30 feet apart, the upper of which is conglomeritic.
The strike of the rocks at the foregoing exposure is southwest and
northeast, dip 20° to 30° SE.
Fossils from No. 3 {field No. 299).
Ostrea sp.
Exogyra costata Say var.
Inoceramus sp., fragments of a large form. Trigonia sp.
Cyprimeria sp., the same as for field Nos. 297 and 298.
Overturned Fold North of Shaft of San Carlos Coal Company.
A short distance north of the shaft of the San Carlos Coal Company
there is a small overturned fold accompanied by an overthrust fault. On
the overthrust side of the fault a fossiliferous horizon is exposed, but it
1 The information concerning what part of the coal seam would coke was furnished by Mr. Maloney,
mine superintendent. Samples of the coke were furnished by the mine officials. ' Or more.
Section in arroyo northeast of shaft of San Carlos Coal Company, 2 miles east of south of San Carlos.
(PI. XI, fig. 26.) Foot.
I. Soft yellow sandstone 10
0. Yellow clays - 10
9. Ledge of soft yellow sandstone 15
8. Clay. 7. Coal, upper seam.
6. Clay. 5. Coal, lower seam.
4. Soft yellow sandstone 6 3. Bluish clay, with fossils, Cyprimeria, Inoceramus, Exogyru, etc 35 2. Layer of clay containing many limestone nodules and fossils 1 1. Clay.
