204 COAL FIELDS OF THE COLORADO RIVER. 



the strata shows a much greater dip than 30 feet to the mile, which would 

 be so near the horizontal that no inclination would appear on the ordinary 

 outcrop. 



The sandstone series, which may be the equivalent of the millstone grit, 

 has on this basis a possible thickness of 4500 feet. The Colorado flows 

 through it from Milburn to a point 8 miles below the mouth of the San 

 Saba River, a distance of 70 miles. The greatest cross section is 40 miles, 

 from a point about 20 miles northwest from Lampasas to a point 5 miles 

 south of Brownwood. East of Brownwood the upper beds of this series dis- 

 appear beneath the Cretaceous, and from this place they strike southwest to 

 Rochelle, in McCulloch County. The eastern extension is buried by the 

 Cretaceous east of the Colorado, and on the south the sandstone beds have 

 been eroded away from the Lower Carboniferous, so that in no place are 

 they found actually resting on the Silurian, although they must once have 

 done so, since the material in the various conglomerate layers is almost en- 

 tirely derived from Silurian formations. The western part of Lampasas 

 County and the entire area of San Saba County, which lies in the true Car- 

 boniferous, is underlaid by this sandstone rock, as well as the Carboniferous 

 corner of Mills County, the southeast corner of Brown, and a strip on the 

 eastern border of McCulloch. Owing to its characteristic development along 

 Richland Creek in San Saba County, I propose for this division of the Car- 

 boniferous the name of "Richland Sandstone." 



This great thickness of sandstone covers an area of more than 1000 square 

 miles. In general it consists of many beds of sandstone, with occasional 

 beds of shale, as for instance on Elliott and Antelope creeks. The various 

 beds of sandstone are of every conceivable grade of coarseness, from the 

 shale to the conglomerate, though the latter rock is strikingly rare. The 

 sandstone is generally yellow and white, containing much iron, which gives 

 the weathered rocks a deep red or yellow color. In form of bedding the 

 sandstone presents every grade, from the fissile shaly sandstone to massive 

 thick-bedded layers, which in weathering form immense blocks as a talus 

 to the hills. This is strikingly shown at various places along the Colorado, 

 particularly near the mouth of the San Saba River. The fossil remains in 

 the Richland Sandstone division present no great range of form, but are con- 

 fined almost exclusively to some of the most durable coal plants washed from 

 the land, and these are very common. 



Conglomeritic sandstone layers are very often encountered throughout the 

 series, but they are more often fine grained, and a breccia rather than a con- 

 glomerate. The Richland Sandstone beds are terminated in the upper por- 

 tion by a band of conglomerate, of variable thickness, and extending from 



