:'>i; Watson and Powell — Age of Virginia Piedmont Slates. 



schists, conglomerates, and slates. No fossils have been found 

 in the sedimentary rocks of this area, but their correlation with 

 the Loudoun is conclusive, although the evidence cannot be 

 presented here. 



The Keswick-Esmont slate area in Albemarle County in- 

 cludes in its northern portion the following succession of rocks 

 extending eastward from Charlottesville: Monticello schist 

 (Catoctin schist of Keith), derived chiefly from a basic volcanic 

 rock, basalt, of Algonkian age, followed by a series of sedi- 

 mentary beds of fine and coarse conglomerate, sandstone, slates, 



Fig. 2. 



Granites and gneisses chiefly 

 Probably pre-Cambrian 



Co astal Plain formations 

 Cretaceous and Tertiary 



Fig, 2. Geologic map of northeastern Virginia, showing the northern 

 half of the Quantico slate belt. 



and limestones of Cambrian age. No fossils have been found 

 in these beds, but the evidence strongly favors their being Cam- 

 brian in age, and they have been so mapped and described.* 



Quantico Slate Bell. 



The Quantico slate belt is so named from Quantico Creek in 

 the southern part of Prince William County. It has been 

 "traced as a narrow belt averaging about one mile in thickness 



* Lambeth, W. A. Notes on the Geology of the Monticello Area, Virginia. 

 A Thesis, University of Virginia, June, 1901. 



