TY  - RPRT
TI  - Map showing extent, altitude of base, and thickness of Potomac Group in Fairfax County, Virginia
AU  - J. D. Larson
AU  - A.J. Froelich
PY  - 1977
DO  - 10.3133/ofr77286
UR  - https://pubs.usgs.gov/publication/ofr77286
ID  - ofr77286
ER  -