CARBONIFEROUS SYSTEM. 155 



appeared the same coral Chaetetes radians as at Bend and elsewhere. The 

 massive limestones of the Carboniferous rocks are the only rocks exposed 

 near the creek. On top of the hill west of Post Oak Creek there is a bed 

 of sandstone four feet thick. The court house and other buildings at Brady- 

 are constructed of this material. 



In many places along Brady Creek is a coarse conglomerate composed of 

 pebbles from the surrounding hills. Two miles above Melvin's Ranch house 

 a heavy bed of this conglomerate overlies the Carboniferous limestone. 



The country westward up Brady Creek is a level plateau, with Cretaceous 

 hills on both sides, and the Carboniferous in the valley of the creek. Three 

 miles east of the town of Eden, in the bed of the creek, there is a rough 

 limestone containing Productus semireticulatus, Euomphalus, Pinna, Nautilus, 

 and stems of Encrinites. 



The higher hills from here to Kickapoo Creek are Cretaceous. At the 

 base of the hills the Carboniferous strata appear. In a bluff just below the 

 crossing on Kickapoo Creek there is an exposure of 20 feet of Carboniferous 

 beds overlaid by the Cretaceous. The Carboniferous has yellow clay at 

 the bottom, then 2 feet of sandstone, then 18 feet of sandstone and shale, 

 with Productus semireticulatus; conglomerate on top. 



After leaving the creek the Lipan Flat is reached, which continues to near 

 San Angelo, with scarcely a break and no exposure of the formation. The 

 Cretaceous hills are seen far to the southward, and later they are seen di- 

 rectly to the west and northwest. 



San Angelo is situated on the west or north side of the North Fork of the 

 Concho River. The river near the town cuts through the conglomerate, and 

 in other places the conglomerate extends entirely across the stream. Below 

 the conglomerate is a white sandstone 18 inches thick; below the sandstone 

 is a bed of green and red clay. 



In the marl is a thin seam of carbonate of iron. Southwest of the town, 

 at a distance of eight miles, red clay was found which very much resembles 

 the red beds of the Permian. 



Above the red clay is a whitish sandstone with bands of iron ore, but the 

 iron is not in sufficient quantities to be of any commercial value. Still 

 further to the westward appear the high hills of the Cretaceous. These hills 

 are separate peaks formed by erosion. On top is the thick compact lime- 

 stone, below which is the Trinity sand, and below that the reddish clay which 

 is always found at the foot of the Cretaceous in this part of the country. The 

 peaks are one hundred and fifty feet high above the Permian clays. 



Further south, in the valley of the main Concho, a bed of sandstone was 

 observed that is evidently Permian, resting upon the red clay; and at the 

 old town of Ben Ficklin, on the east side of the Main Concho, was found a 



