TY  - RPRT
TI  - Origin of Pennsylvanian underclay and related seat rocks
AU  - J. W. Huddle
AU  - S. H. Patterson
PY  - 1961
DO  - 10.1130/0016-7606(1961)72[1643:oopuar]2.0.co;2
UR  - https://pubs.usgs.gov/publication/70206836
ID  - 70206836
ER  -