156 SOUTHERN BORDER OF CENTRAL COAL FIELD. 



rock quarry of argillaceous sandstone in several layers. In the stone were 

 found Permian fossils, which show the blendings of the old and new forms 

 of life. In the stone were found species of Productus, Ammonites, Aviculopec- 

 ten, Orthoceras, Nautilus, Myalina, and several other forms that were not identi- 

 fied. The fossils are very similar to those in the Permian in the northeastern 

 part of Baylor County. 



Among the number of specimens is what appears to be a new Aviculo- 

 pecten, that I have previously called A. costatus. 



Below the stone is a bed of green clay three feet thick, and below that a 

 bed of dark red clay. Bottom not seen. 



CONGLOMERATE. 



There are two kinds of conglomerate found in this part of the State; one 

 of them composed of small much water- worn siliceous pebbles of various 

 colors, bound together sometimes by an iron matrix and sometimes by a 

 siliceous matrix. This conglomerate is generally very hard, and is more 

 often found as bowlders, yet at places it covers many square acres and seems 

 to be in place. It has been thought that these bowlders were left in their 

 present locality by glaciers, but I am sure they are only the remains of a 

 more extensive deposit that was destroyed at the period of erosion. This 

 conglomerate does not occur as a regular stratum in the series, but is found 

 overlying nearly every stratum in the Carboniferous. It seems to be the 

 same conglomerate that is found overlying the Carboniferous formation in 

 the northern part of the State, of which mention is made in my report pub- 

 lished in the First Report of Progress of the Survey last winter. It is not so 

 universally distributed in this part of the State as it is further north; at least 

 it seems to have been more nearly destroyed. 



This conglomerate in some localities is very compact, and the bowlders 

 are worn smooth by the driving of sand against them by the wind. The 

 materials of these bowlders are usually bound together by a siliceous cement 

 so compactly that they are as solid as a single mass of quartz, and receive an 

 excellent polish and are very beautiful. 



Associated with this conglomerate are the only specimens of petrified 

 wood I have seen, and yet they are not associated in such a way as to show 

 that they were deposited at the same time. 



There is another conglomerate found along all the rivers and creeks, made up 

 of fragments of stones from the surrounding strata. This conglomerate was 

 deposited at the same time of the erosion, some of it evidently in the early 

 part of that epoch, and some of it at the very last. I conclude that such is the 

 case from the different heights at which it occurred. At the Colorado River, 

 on the hills west of McAnnelly's Bend, a bed of this conglomerate 7 feet 



