286 GEOLOGICAL EXCURSION TO THE ROCKY MOUNTAINS. 



The fauna of this scries belongs to extreme Upper Carboniferous 

 types, and some forms are closely related to Permian species, while the 

 flora above the middle of the series is also of Permian aspect. 



Feet. 



g| ii i 



Maximum thickness (ou the Great Kanawha in West Virginia) 



Minimum (in Ohio) "'" 



Average thickness *'"" 



The Upper Coal Measures, Monongakela River Series (XV). — These 

 beds crown the summit of the mountain in the bottom of the synoline 

 at Piedmont, the principal coal (the Pittsburg) being known there as 

 the "Big" bed, smce along George's Creek, between Piedmont and 

 FTostburg, it is often 20 feel t hick, and is mined and shipped under the 

 name of Cumberland coal. This greal bed of valuable fuel is the basal 

 member of the Upper Coal Measures, and is the most important stratum 

 in the Appalachian field. It is the celebrated Connellsville coking coal, 

 the Westmoreland and Penn gas coal, the shipping coal all along (he 

 Monongahela River, and extends under a vast area between (hat stream 

 and the Ohio River. 



A small remnant of it is found in the summits of the hills at Newburg, 

 and the Baltimore and Ohio Railroad does not cross its outcrop again 

 until we conie to the town of Fairmont, where, at Monongah, Gaston, 

 Montana, and West Fairmont, it is extensively mined for coking, gas, 

 and general fuel purposes. 



Westward from Fairmont it dips down below water level, being -100 

 feet below the valley at Mannington and 800 i'vet at Board Tree, where 

 it is 1,600 feet under the highest summits. Rising westward from the 

 center of the great Appalachian trough at Board Tree, il comes to the 

 surface again at Bellaire and furnishes valuable fuel for that city and 

 Wheeling. 



The rocks above the Pittsburg coal in Pennsylvania, northern West 

 Virginia, and Ohio are mostly limestones and calcareous shales, with 

 some sandstone, and four other coal beds, viz. in ascending order: 



Redstone. Sewickley. TJniontown. Waynesburg; this last topping 

 out the scries. 



Southwestward through West Virginia and southern Ohio, the lime- 

 stones are replaced by red shales and the last four coals practically 

 disappear, while much massive sandstone comes into the column. 



This series has an average thickness of 360 feet along the Mouonga- 

 hela river, but it thins to 250 feet in Ohio and thickens to 413 feet in 

 the central portion of the Appalachian trough. 



The Permian, hunkurd Creek Scries (XVI). — This scries of beds tops 

 out the Carboniferous system in the Appalachian field, and has its 

 greatest development along the Baltimore and Ohio Railroad between 



