i08 Featherstonhaugh''s Geological Report. 



made, which crosses this slope at an elevation of five hundred 

 feet, over which a careless traveller might be easilj precipi- 

 tated. This was a section of Dan's mountain, which I had 

 before crossed on my way to Frostburg. On descending the 

 east side of this mountain, I came in view of a most striking: 

 section of the limstone beds on the opposite bank of the Poto- 

 mac, where the flexure of the rocks was occasionally con- 

 tinued in an anticlinal and synclinal line, upon a large scale, 

 and the surface had been so curiously removed in various 

 parts, that sometimes a perfect arch w^^s left, and at other 

 times an inverted one. Diagram No. 15 represents one of 

 these sections. 



From Cumberland I now went in a northerly direction near 

 forty miles to Bedford, along a valley between Wills's moun- 

 tain on the west, and Evitt's mountain, a somewhat smaller 

 ridge, on the east. The red shale which underlies Wills's 

 mountain at Cumberland, constantly appears subordinate to 

 the sandstone on this route. The valley abounds with knolls 

 of limestone, containing fossils of the carboniferous limestone, 

 resembling the knolls in Alleghany county, Virginia, lower 

 down on this range, about two hundred miles south, in the 

 vicinity of the Sweet springs. The constancy of the phenomena 

 connected with the anticlinal arrangement of the whole series 

 of Alleghany ridges, seems to suggest the true explanation of 

 their origin. Prior to this undulating elevatory movement, 

 the level of these beds seems not only to have been higher, 

 but to have been continuous and without valleys. Whilst 

 some parts of the strata were forced up into the anticlinal 

 form, in a constant magnetic direction, the intervening distance 

 betwixt each axis or ridge would probably be thrown into a 

 ruinous state, and as the dry land rose and the waters retired, 

 the ruins would at length be borne away, and the valleys re- 

 main. All these ridges, how^ever, are not in a perfectly anti- 

 clinal state at present. At Prospect rock, at the top of the 

 Cacapon mountain, in Morgan county, Virginia, the strata have 



