TY  - RPRT
TI  - Government Draw Bentonite Beds: a newly identified stratigraphic marker in the Virgin Creek Member of the Pierre Shale, central South Dakota ( USA).
AU  - T. C. Nichols
AU  - A.F. Chleborad
AU  - D. S. Collins
PY  - 1987
UR  - https://pubs.usgs.gov/publication/70015272
ID  - 70015272
ER  -