TY  - RPRT
TI  - The lower Pennsylvanian unconformity in the central Appalachian Basin
AU  - R. E. Thomas
AU  - K. J. Englund
PY  - 1999
DO  - 10.3133/i2597
UR  - https://pubs.usgs.gov/publication/i2597
ID  - i2597
ER  -