WEST VIRGINIA GEOLOGICAL SURVEY. 135 



eastern Lewis it is not prominent but in southwestern Free- 

 mans Creek District, it becomes a great massive gray cliff, 

 often 50 feet thick. It is prominent along Alum Fork of Lead- 

 ing Creek, north of Alum Bridge. This stream derives its 

 name from an alum spring located on the land of Charles 

 Stark, 0.7 mile north of Alum Bridge. At this spring the fol- 

 lowing sequence occurs : 



Feet. 

 Sandstone, massive, gray, great cliff, Lower Pittsburgh 



(875' B.) 50 



Shale, gray, with incrustations of white alum, Little 



Pittsburgh Coal horizon 0*& 



Shale, sandy 5 



The water, which has a strong alum taste, flows out of 

 a crevice in the sandstone, about one foot above its base, its 

 volume being estimated at 30 to 40 gallons daily in extremely 

 dry weather. The immediate source of this water seems 

 without doubt to be in the sandstone ledge, its alum content 

 being probably a mineral of secondary formation resulting 

 from the infiltration of sulphate of iron from the Pittsburgh 

 Coal seam, which lies just above, acting upon the aluminous 

 material contained in the body of the sandstone. 



In Gilmer the Lower Pittsburgh Sandstone is usually 

 present in massive form. In western Troy, western Glenville, 

 Dekalb and Center Districts, where the Pittsburgh Coal is 

 seldom found, this sandstone proved to be a valuable aid in 

 tracing the latter's horizon for structural purposes, since it 

 usually is resistant enough to make a broad shoulder, the 

 top of which, approximately coinciding with the coal horizon, 

 can be readily followed by eye. In portions of Center Dis- 

 trict, the Lower Pittsburgh Sandstone coalesces with the Con- 

 nellsville below it to form a huge single cliff. At the mouth 

 of Steer Run, one mile southeast of Normantown, this cliff 

 is 75 feet thick, with a tidal elevation of 870' B. No quarries 

 were observed on this sandstone but it would make good 

 material for bridge abutments and other structures where 

 large blocks are desired. 



