TY  - RPRT
TI  - The river and the rocks: The geologic story of Great Falls and the Potomac River Gorge
AU  - John Calvin Reed
AU  - Robert Sumner Sigafoos
AU  - George Wescott Fisher
PY  - 1980
DO  - 10.3133/b1471
UR  - https://pubs.usgs.gov/publication/b1471
ID  - b1471
ER  -