A. Redefinition of Frontier Formation-Beaverhead Group contact, Lima Peaks area, southwestern Montana and southeastern Idaho / by T.S. Dyman, J.C. Haley, and W.J. Perry, Jr. -- Biostratigraphic correlation of Santonian and Campanian formations in the northwestern part of Yellowstone National Park, Madison Range, and Livingston area of southwestern Montana / by R.G. Tysdal and D.J. Nichols -- Occurrence and significance of the middle Turonian (Upper Cretaceous) belemnite Actinocamax in central western Montana / by William A. Cobban.