1. A stratigraphic and structural study of the Eram coal and associated strata in eastern Okmulgee County and western Muskogee County, Oklahoma [cartographic material] Yale Public content 1988. 2016-03-03T18:04:36Z. 2016-07-26T21:16:10Z. Hemish, LeRoy A. University of Oklahoma. English. cartographic image. Public. Oklahoma, Okmulgee County, and Muskogee County.