PENNSYLVANIAN STRATIGRAPHY OF TEXAS 35 



Colorado Valley has been named the Rochelle conglomerate, and a 

 thin lentil of limestone which is traceable for a considerable distance 

 in the lower part of the Brownwood in Brown County is named the 

 Capps bed. The Adams Branch limestone has a thickness of 10 

 to 30 feet in the southern Pennsylvanian area, but northward it 

 increases locally to more than 100 feet. A varied fauna has been 

 collected from the Graford formation, the most numerous fossils 

 coming from the Brownwood member. While it contains some 

 species, in part undescribed, not known in the Wewoka fauna, and 

 lacks many which occur in the southern Oklahoma formation, it is 

 a local modification of this fauna and corresponds to it more closely 

 than to any other. A thin bed about 60 feet below the top of the 

 Adams Branch limestone, characterized by an abundance of a very 

 elongate, emaciated Fusulina, has been identified throughout the 

 extent of this member. 



The Brad formation, named from Brad in Palo Pinto County, 

 rests conformably upon the Graford. It consists of limestone and 

 shale, a massive, very cherty limestone, the Ranger member, mark- 

 ing the top. The Brad formation has been traced from near 

 Stewarton in Jack County to Brady in McCullough County, its 

 average thickness in the north being about 225 feet, and in the 

 south about 200 feet. The lower part of the formation consists of 

 shale with thin limestones and some sandstone, and in the north 

 all the strata below the Ranger limestone are included in the 

 Seaman Ranch member. In the Colorado River Valley, however, 

 three members are distinguished below the Ranger: the Cedarton 

 shale and sandstone, 20 to 80 feet at the base; the Clear Creek 

 limestone, 10 to 25 feet, next above; and the Placid shale, 30 to 50 

 feet, beneath the Ranger. The Ranger limestone, which was 

 called by Drake the "Cherty limestone," is readily distinguishable 

 because it is the only uniformly cherty bed in the Canyon. Its 

 thickness ranges from 10 to 50 feet. 



The Caddo Creek formation, named from a tributary of the 

 Brazos in Stephens County, has been mapped from eastern Jack 

 County southwest and south to a point near Brady. In the north 

 its average thickness is 100 to 150 feet, in the south 30 to 50 feet. 

 It consists of two members, both named by Drake in the Colorado 



