CARBONIFEROUS BEDS. 203 



dip under the sandstone if followed a few miles to the west, and the over- 

 lying sandstone would cover it and extend to the Silurian. But such is not 

 the case. The belt of limestone extends continuously for nearly thirty miles. 

 In this series there are many different beds of limestone and shale, one above 

 the other, each one of which strikes up to the sandstone and there stops. 



We have, therefore, an upper sandstone formation, composed of various 

 beds, striking southwest, and overlapping a great thickness of limestone. 

 There is, therefore, no explanation, to my mind, but unconformability; a fact 

 which necessarily proves a different age from that of the overlying coal 

 measures. That they are Lower Carboniferous rather than Devonian is 

 shown by the close resemblance of the fossils of the lower beds to those of 

 the Upper Carboniferous. The field evidences thus seem to prove that these 

 beds are not a part of the true coal-bearing series, but belong to an older for- 

 mation — the Lower Carboniferous. The Lower Carboniferous extends from 

 near Lam*" asas to some distance west of Brady, with an average width of not 

 more than ten miles, and is the formation on which the towns of San Saba 

 and Brady are situated. This will remove all hope of finding coal in quan- 

 tity at either of these places. The conditions which existed when the Lower 

 Carboniferous limestone series was being formed were not favorable to the 

 formation of extensive coal deposits. Such seams of coal as those encoun- 

 tered at San Saba and Brady are the best that can be expected in this forma- 

 tion. Thin beds of an inch or two in thickness and of local extent may be 

 found in various places in these limestones, but it will be useless to prospect 

 for better ones. 



The lowest beds of the true Carboniferous which are exposed in this part 

 of the State are the sandstones on the Colorado, nearly west of Lampasas, in 

 the neighborhood of Nix Postoflfice. This is the beginning of a great thick- 

 ness of sandstone, having, in common with al] the beds of the series, a very 

 gentle dip to the northwest. With some few exceptions of local importance, 

 the dip is uniform in that direction. The amount of dip is difficult to esti- 

 mate without accurate instrumental measurement, which will be done in time 

 for the final report on the coal measures. A careful examination of many 

 hundred exposures shows considerable variability in the dip. There are 

 places where it is as great as five degrees, but such instances are rare and 

 very local. Again the rocks are almost perfectly horizontal, or even re- 

 versed, thus dipping to the southeast. To choose between these and select 

 the normal is a difficult task in a region of gently dipping rocks where a 

 superficial dislocation of a few feet will reverse the apparent dip. This dip 

 has been previously estimated at 30 feet to the mile, but this, I am confi- 

 dent, is entirely too small. Many measurements which I made on outcrops 

 average much more than 100 feet to the mile, and the general appearance of 



