CARBONIFEROUS SYSTEM. * 151 



the even grained gray sandstone, which is about six feet thick. In the sand- 

 stone were found impressions of Carboniferous plants, Catamites, etc., but no 

 other fossils were observed. This stone has been used in the town of San 

 Saba and vicinity for building, for which purpose it is a fine material. 



Crossing the San Saba River north of Richland Creek,- and traveling up 

 the divide between it and the San Saba River, there is found near the mouth 

 of the creek, on the north side, a hill showing the bluish and yellowish clay 

 at bottom with the sandstone four feet thick at the top. At several places 

 along the way the same formation is seen, but always on the north side of 

 the road. On the south side, in the creeks running into the San Saba, the 

 black shales appear. At Richland Springs, on the slope of the hill, are found 

 the thin-bedded limestones with thin seams of black shale, as seen at other 

 places. These black shales are also found on Job's Creek, a few miles south 

 of this locality, where they contain the same fossils as at Bend. Some of the 

 houses in the town of Richland Springs are built of a light stone which is 

 here the equivalent of the upper stratum at Indian Bluff. Carboniferous 

 sandstone is found near this place on the north side of the creek. 



One mile above the crossing of the Colorado, north of Milburn, McCulloch 

 County, and on the north side of the river, is an exposure of strata 80 

 feet thick, composed of blue shale, with thin beds of sandstone, having a 

 massive sandstone on top. In the shales, and in a thin stratum of shell con- 

 glomerate, were found the following fossils: Productus nebrascencis, Aihyris 

 subtilita, Aviculopecten occidentalism Myalina subquadrata. 



From the Colorado River to the head of a prong of Clear Creek, on the 

 Brady and Brownwood road, occasional exposures of the Carboniferous sand- 

 stones were seen. On the head of Clear Creek the massive limestone of the 

 Carboniferous was again found, but no fossils were to be obtained. 



In this limestone, near Trickham, are some very large Campophylla associ- 

 ated with Fusulina cylindrica. The shaly limestone is 20 feet thick, and is 

 underlaid by a blue clay, as is shown by well borings. t 



One mile north of the town is a hill some 60 feet high. The bottom is 

 composed of shale, with nodules of clay ironstone, and the top is capped with 

 a massive sandstone 8 feet thick. ' The sandstone here is coarser in structure 

 than is usually seen in the Carboniferous. 



On a hill still further northwest is a compact limestone above 1 feet of the 

 shale, which here overlies this sandstone. The dip of the strata is to the 

 northwest. 



In Dunson and Kingsbury's pasture, 6 miles west of Trickham, there is an 

 exposure of the same strata, with sandstone 4 feet thick on top; yellow 

 clay 10 feet thick, and bluish clay 8 feet thick at the bottom. In the yellow 

 clay there are a great many nodules of clay ironstone, and in the nodules 



