1. Distribution, thickness, overburden, and structure contour maps of potentially recoverable lignite beds in the eastern part of the Fort Peck Indian Reservation, Montana [microform] Yale Public content 1988. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey : [Books and Open-File Reports Section, distributor]. English. Public. Montana and Fort Peck Indian Reservation.