M'Gonigle, John W. <br/><br/>
40Ar/39Ar ages of some Challis Volcanic Group rocks and the initiation of Tertiary sedimentary basins in southwestern Montana / 
by ... and G. Brent Dalrymple 
 - Washington :  U.S. Govt. Print. Off.,  1996 
 - 17 p. :  maps (in pocket) 
 - Bulletin ;  no. 2132 .
 - United States.  Geological Survey.  Bulletin ;  no. 2132 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Rocks, Igneous--Montana<br/>Argon-argon dating--Montana<br/>Geology, Stratigraphic--Tertiary
<br/><br/><label>LC Class. No.: </label>QE75  / B9 no. 2132