1. Stratigraphic framework and coal resources of the Upper Cretaceous Blackhawk Formation in the Trail Mountain and East Mountain areas of the Wasatch Plateau Coal Field, Manti 30ʹ x 60ʹ quadrangle, Emery County, Utah Yale Public content 1986. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Branch of Distribution. English. Public. Utah and Emery County. Cretaceous.