Mount Rogers Formation - Porphyritic felsite

Includes coarsely porphyritic felsite from the Pond Mountain volcanic center that could be a hypabys sal intrusive, and porphyritic rhyolite from the Razor Ridge volcanic center that is extrusive, as well as the Fees Rhyolite Member near the base of the formation.
State Virginia
Name Mount Rogers Formation - Porphyritic felsite
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic
Comments In Grayson, Washington, and Smyth Counties only; Blue Ridge Anticlinorium (Southwest)
References

Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.

Virginia Division of Mineral Resources, 2003, Digital Representation of the 1993 Geologic Map of Virginia, Publication 174, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, scale 1:500,000.

NGMDB product
Counties Grayson - Washington