WILLIAMS.) 



WASHINGTON TO CUMBERLAND. 



279 



Oriskany sandstone. Beyond Keyser the road crosses the Potomac 

 into West Virginia, and fine exposures of Hamilton shales are seen in 

 the cuts. The road now bends to the northwest and crosses, at right 

 angles to the strike, steeply dipping beds of the Devonian and of the 

 Carboniferous np to the Coal Measures, a thickness of about L3,000 feet 

 (4,000 m.) of rock strata. 



FROM CUMBERLAND (MD.)TO THE OHIO RIVER. 



By I. C. White. 



Tin* area across which the Baltimore and Ohio Railroad passes from 

 Cumberland westward to the Ohio River includes all of the Alleghany 

 Mountain country proper, and also about three fifths of the breadth 

 of the great Appalachian coal Held, the eastern line of which is found 

 only five miles northwest from Cumberland, and the western margin 

 of the same near Newark, Ohio. The airline distance across the 

 Appalachian held along the line of the Baltimore and Ohio Railroad 

 is about 104 miles, but the distance by rail between Cumberland and 

 Newark, the two margins of this coal field, is 315 miles. 



Cast Front Ridge 



Kk;. 7— Section across th<> Alleghany Mountains to the Ohio River. 

 IS Permian. lvTJpperCoal Measures. 14>> Lower Coal Measures. U* Millstone 



tain linn stone- and .Maud) Chunk slial 



13* PoCOnO Sandstone 



rit. 18* Moun- 

 12 ( 'at skill, li < rhemung. 



As shown by the above illustration of the geological structure, the 

 rocks of the Alleghany Mountain country are crumpled up into a series 

 of large folds, and these, together with the great erosion to which the 

 region has been subjected, have produced the wild and rugged scenery 

 between Piedmont and Rowlesburg. 



The Pottsville Conglomerate (XII), and the Pocono sandstone (X) 

 are the mountain -makers of the Alleghanies, while the great anticlinal 

 ridge (Wills Creek Mountain i, through which the Baltimore and Ohio 

 Railroad leaves Cumberland for Pittsburg, is made by the White Medina 

 sandstone (IV) at the base of the Upper Silurian. 



Westward from the Alleghanies proper the folds in the strata 

 become gradually more gentle, and dually die away, before reaching 

 t he Ohio River, into low undnlat ions of the beds, which are so insignifi- 

 cant as to be almost imperceptible to the eye. 



The great arches already referred to bring up the lowest rocks of the 

 legion in the vicinity of Cumberland, so that from there westward we 

 pass upward through the geological scale from The middle of the Medina 



