102 Feather stonhaugVs Geological Report, 



tion. The canal not being navigable bejond this town, which 

 is one hundred miles from Georgetown, I abandoned those in 

 structive banks of the river, and continued over the limestone, 

 occasionally alternating with shale, by the upper route, to 

 Clear Spring, about seven miles. A little beyond this place 

 the formations change, and the heavy limestone water is ex 

 changed for the pure springs flowing from the shales and 

 sandstones of the north mountain, the first in advance of the 

 Alleghany system of ridges west of the Atlantic primary. Fur 

 ther on, about nine miles, a fine fossiliferous bed of limestone 

 comes in on the Licking creek, containing producta, spirifers, 

 cardia, and some goniatites. There is, however, a lower 

 route, by the way of what is called Big Spring, betwixt the 

 North mountain and the river, where the limestone, with the 

 exception of a few continuous beds of shale, is continous ; and 

 as the North mountain, on the Virginia side, across the Poto 

 mac, continues its course to the S. S. W., it is evident that 

 the bed of the river has been excavated subsequent to the 

 deposite of the North mountain, and that the shales and sand 

 stones have been removed from the limestone occupying the 

 space between the now separated portions of the mountain. 

 I have subsequently had an opportunity of examining the 

 country on the Virginia side, and found every thing in cor 

 respondence there. The limestone extends from Shepherds- 

 town to the east flank of the North mountain, near Hedges- 

 ville, and the same beds of shale which are observed on the 

 opposite side, occur on this side, betwixt this last-mentioned 

 place and Martinsburg. Pursuing the road from Licking 

 creek to Hancock, there are numerous sections of shales and 

 sandstones, dipping alternately east and west, the strata fre 

 quently exhibiting imperfect arches. On the route a very 

 distinct view is had of a narrow 7 valley, on the Virginia side, 

 lying between two subordinate ridges, called the Third hill 

 and Sleepy-creek mountain. Here the first veins are found 

 of anthracite coal of a good quality ; and although they are 



