Gill, James R.  1922-1972 <br/><br/>
Stratigraphy and geologic history of the Montana group and equivalent rocks, Montana, Wyoming and North and South Dakota / 
by J. R. Gill and W. A. Cobban 
 - Washington, D.C. :  United state government printing office,  1973 
 - ii, 37 cm. ;  28 cm. 
 - Geological Survey professional paper ;  no.776 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology, Stratigraphic--Cretaceous<br/>Geology--West (U.S.)
<br/><br/><label>Dewey Class. No.: </label>551.720978