TY - RPRT TI - Preliminary stratigraphic cross section showing radioactive zones in the Devonian black shales of the central part of the Appalachian basin AU - John B. Roen AU - L.G. Wallace AU - Wallace De Witt PY - 1977 DO - 10.3133/ofr77841 UR - https://pubs.usgs.gov/publication/ofr77841 ID - ofr77841 ER -