Deep drilling in the exploration for oil during the past few years has revealed the northern Montana Paleozoic section in the plains of southern Alberta. Records of the Paleozoic of the deep wells in the Kevin-Sunburst field, especially the Adams No. 1, on the Potlatch lease, are compared with those of southern Alberta. Distance from exposures and type localities impose difficulties on correlations, because great lithologic changes occur in the intervals. Most notable are those strata assigned to the Three Forks, composed mostly of a thick massive anhydrite zone. The thin widespread sheet of black shale is chosen as the upper member of the Three Forks formation.