GEOLOGICAL SOCIETY OF PENNSYLVANIx\. 



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by hills having no outlet, are gradually filling up from 

 the detritus of the surrounding rocks. These clays thus 

 deposited, are used for making bricks. 



These talcose-slate lands might be much improved by 

 the addition of lime, a bed of limestone existing near the 

 confines of the Gold Belt. 



The surface of the land being undulating, is conse- 

 quently adapted to mining operations, allowing the loca- 

 tion of adit levels/ by which the mines, can be drained to 

 a limited depth. Some of the waters have a sensibly 

 ferruginous taste. The hills are not higher than about 

 150 to 200 feet above the Rappahannock, and have but 

 few precipitate faces, save on the rivers. The rocks that 

 show themselves in the gold region of this part of Virgi- 

 nia, are talcose and chlorite shales, protogine, jade and 

 steaschiste. These rocks have a direction from south 

 west to north east. They are highly inclined, deviat- 

 ing from perpendicularity only a few degrees, towards 

 the south east. 



The talcose slate is here generally a red rock, dividing 

 into long thin laminse, with a silk-like silvery lustre, hav- 

 ing that usual talcose or soapy touch, that characterizes 

 magnesian rocks. They are of easy disintegration on the 

 surface of the earth, and may be generally worked with 

 a pick below. These rocks mix the one with the other, 

 and give a great variety of colours within a space of a 

 few feet. When the chlorite is most abundant, the rock 

 is green : ferruginous matter gives a variety of tinges, 

 from a dark to a light red. These colours do not alter 

 the general character of the shales, which in the majo- 

 rity of cases may be worked without blasting, though 

 at times the schistose structure is lost, and the rock be- 

 comes more petro-silicious, passing into a hard and com- 

 pact protogine. Near the Union gold mines, steaschiste 

 occurs with amianthus. A quarry of this rock was open- 

 ed on the river Rappahannock, at Barnitz Mills. Jade 



