TY  - BOOK
AU  - Gill,James R.
AU  - Cobban,William Aubrey
TI  - Stratigraphy and geologic history of the Montana group and equivalent rocks, Montana, Wyoming and North and South Dakota
U1  -  551.720978 
PY  - 1973///
CY  - Washington, D.C.
PB  - United state government printing office
KW  - Geology, Stratigraphic
KW  - Cretaceous
KW  - Geology
KW  - West (U.S.)
ER  -