528 Butts — Geologic Section of Blair and 



main line of the Pennsylvania Railroad between Birming- 

 ham and Shoenberger. 



The Gatesburg is correlated by Ulrich with a gronp of 

 dolomite formations in central Alabama, lying between 

 Ulrich's Copper Eidge dolomite and the top of the Con- 

 asanga limestone, the npper part of the Conasauga being 

 regarded as the equivalent of the Nolichucky shale. 

 These formations are the Briarfield dolomite of Ulrich, 

 the Ketona dolomite, and some overlying beds of dolomite 

 called Potosi by Ulrich in his Revision. The Larke, 

 Mines, and Gatesburg should probably be correlated in 

 general with the Conococheagne limestone of the Cham- 

 bersburg and Mercersburg regions of Pennsylvania. 



The Warrior limestone is named from Warrior Creek, 

 in the northern part of Huntingdon County, east of 

 Warrior's Mark. This limestone has been called the 

 Buffalo Run limestone by Walcott (Smithsonian Miscel- 

 laneous Collection, vol. 64, p. 165), who adopted, without 

 definition, the field name used provisionally by Prof. 

 Moore. The best exposures of the Warrior limestone 

 are at the type locality on Warrior Run, along the river 

 bluff a mile west of Williamsburg, and in the western 

 half of Bloomfield township, Bedford county, several 

 miles south of Roaring Spring and on the Everett quad- 

 rangle. 



The Pleasant Hill limestone is named from Pleasant 

 Hill church a mile northwest of Henrietta, in the south- 

 east corner of Blair County, where the upper part, the 

 limestone, is excellently exposed. Ulrich regards both 

 the Warrior and the Pleasant Hill as Upper Cambrian 

 and Walcott regards the Warrior as Upper Cambrian. 

 Probably the Warrior and Pleasant Hill are in part rep- 

 resented by local beds of relatively pure limestone that 

 have been somewhat doubtfully included in the upper 

 part of the Elbrook limestone of Maryland and Penn- 

 sylvania. 



" The mapping of these limestone units has resulted in 

 the detection of a number of hitherto unknown faults, 

 some of considerable magnitude in both displacement and 

 linear extent. For example, there is a great fault or 

 narrow belt of overlapping faults of several thousand feet 

 displacement extending from the northwestern part of 

 Hopewell township, Bedford County, northward to Birm- 

 ingham, on the main line of the Pennsylvania Railroad, 



