WEST VIRGINIA GEOLOGICAL SURVEY. 43 



On the eastern side of the basin, the rocks rise continuously 

 southeastward at a rapidly increasing rate all the way to the 

 southeastern corner of Lewis County. 



The surface geology is principally that of the Dunkard and 

 Monongahela Series, the Conemaugh cropping only along Oil 

 Creek and Clover Fork. The Pittsburgh Coal horizon is 

 almost level along the axis of the basin. At the north end it 

 is 925 feet above sea level, but rises to 975 at Canoe Run, where 

 there is a structural saddle at this level. Along the axis on 

 Oil Creek and Clover Fork, the coal is slightly less than 975 

 feet. 



Unconformities and Faults. 



There are no unconformities of consequence visible in the 

 surface rocks of the two counties. Some of the geological 

 series, as will be explained later, do not reach their maximum 

 development as compared to other portions of the State, but 

 the principal features are represented and the intervals are 

 fairly constant. Underground, however, the records of bor- 

 ings reveal the usual unconformity, known to exist generally 

 throughout the Appalachian region, between the base of the 

 Pennsylvanian and the top of the Mississippian. Along the 

 western edge of Gilmer almost the entire Mauch Chunk Series 

 is found to have been eroded before the deposition of the 

 Pottsville above it, the thickness of the former in some places 

 being less than 100 feet, while in eastern Lewis it sometimes 

 exceeds 400. The erosion that took place along the eastern 

 edge, where the maximum thickness of Mauch Chunk sedi- 

 ments is found, is a matter of speculation entirely, as, so far 

 as is known, no facts are obtainable on which to base an esti- 

 mate. The sharp lithologic change, however, from red shale 

 to coarse conglomeratic gray sandstones, indicates a long lapse 

 of time as well as a marked contrast in conditions of sedimen- 

 tation. 



So far as known there are no faults in either county. 

 None was observed and the structural slopes are too gentle to 

 favor their occurrence. 



