46 PHYSICAL GEOGRAPHY 



variously coloured sandstones thrown up at all degrees of ele- 

 vation and dipping in every direction, witli interposed bands of 

 encriyiital limestone. The highest ridges are invariably capped 

 by white sandstone with a loose texture, in some places disin- 

 tegrated into a fine sand. Some of the rocks in this region 

 contain fossils that are said to be analogous to those of the 

 carboniferous limestone of the western country. The lime- 

 stone is here cavernous — a general character belonging to the 

 blue limestone west of the range of primary rocks — as is 

 shewn by the passage of a part of the waters of Flintstone 

 creek under the Warrior mountain, and their re-appearance on 

 the opposite side. Thermal springs, and springs charged 

 with sulphuretted hydrogen, together with some chalybeates, 

 likewise occur in this portion of the state. 



The rocks in the neighbourhood of Hancock are also fossi- 

 liferous, containing Trilobites, Producti^ Spirifers, &c. they 

 present the same recurrence of limestones, sandstones, with 

 occasional seams of bituminous shales, and the mountain 

 tops are covered by a fine grained, friable, white sandstone. 

 Specimens of argentiferous galena have been received from 

 this quarter : several localities of iron ore associated with 

 oxide of manganese are known to occur, and in a correspond- 

 ing region on the Virginia side of the Potomac, anthracite has 

 been discovered within the last year. 



The body of the North mountain seems to be composed of 

 slates and red sandstones, with a superincumbent deposite of 

 a more recent white sandstone, in which however, no fossils 

 are known to have been detected. In the valley between this 

 chain of mountains and the South, or Blue ridge, the prevail- 

 ing rock is the blue limestone, which is cavernous ; its strata 

 are higlily inclined, dipping in various and opposite directions 

 and do not contain any organic remains. At the confluence 

 of the Conococheague and Potomac, in the vicinity of Wil- 

 liamsport, the slate rocks appear with lines of fracture, and of 

 stratification so very confused, that it is impossible to ascertain 

 their dip and direction. Near Sharpsburg the rocks are prin- 

 cipally limestones, and on the road from this place to Boons- 

 boro' the rock assumes a variety of colours, constituting blue, 

 yellow, red, fine grained marbles that admit of a good polish. 

 In Pleasant valley, white statuary marbles of superior quality 



