PALEOZOIC GROUP. 291 



the meridianal uplift which began after the Texan Period. Overlying the 

 conglomerate there is a set of limestones, usually thickest where the former 

 is thinnest, and vice versa, but in some places both are well developed. Wal- 

 cott reports 310 feet of "Potsdam limestone" in Packsaddle Mountain. 

 Among these beds he probably included the flags, and perhaps some of the 

 beds of our Middle Cambrian, which might have been mistaken for them in 

 that section, owing to blind faults not discoverable without some detailed 

 study. He is wrong in putting 90 feet of Potsdam sandstone above this 

 limestone, for it is immediately covered by Silurian dolomite. There is a 

 continuous section of the Upper Katemcy Beds north of Bauman's, extending 

 from the east bank of Cold Creek up to within about 50 feet of the summit 

 of Sponge Mountain, where it is capped by the Silurian. In this exposure 

 there are 200 feet of the limestones, surmounting 50 feet of the conglomerate 

 interstratified with limestones. Much of the limestone is impregnated with 

 greensand particles, and the whole is laminated and largely fragmental. 



Several well defined fossiliferous horizons, containing especially numerous 

 mutilated trilobite remains, are included. An interesting discovery is the 

 occurrence of Foraminifera in abundance in some of the greensand limestones. 

 The greensand beds of the lowest division may contain similar fossils, but I 

 have as yet been unable to detect them there. They occur in some of the 

 chocolate and red sand rocks, of uncertain horizon, but apparently of Pots- 

 dam age. Practically the same sections exist in many parts of our district, 

 but the basal contacts are by no means regular. On Deer Creek, in the 

 southwest corner of San Saba County, the Upper Katemcy Beds (Potsdam 

 limestones) seem to be resting conformably upon the Lower Katemcy (Pots- 

 dam sandstone) basal members. At Camp San Saba, at the mouth of Ka- 

 temcy Creek, the conglomerate appears to be nearly absent, although it 

 comes out in full force again in supercontact with the Middle Katemcy strata 

 (Potsdam flags) only a little west of the town. The junction with the Silu- 

 rian is no less variable. All these facts have an important bearing upon the 

 geologic history, but enough has been written to make the salient features 

 understood, and further discussion must be left until a more convenient 

 opportunity. 



