Has two distinct uses, one of which is in the correct, original sense, and one of which needs to be changed to a new name. Originally, Sunset used for lagoonal facies (medium to thick-bedded, shale-poor, micritic limestones) of the C4 sequence in central Kentucky. There, it is mapped as the fifth member of Ashlock Formation, is underlain by the Terrill Member, and overlain by the Reba Member. The Sunset was later expanded to include deep-subtidal facies (thin to medium-bedded, micrite-poor skeletal storm beds and shale) of northern Kentucky, southwestern Ohio, and southeastern Indiana. This latter usage is sometimes placed in quotes, to avoid confusion with the true Sunset near its type area in central Kentucky. The Sunset in Ohio and Indiana is mapped traditionally as a member of the Arnheim Formation, overlies the Mount Auburn Formation and is overlain by the Oregonia Member of the Arnheim Formation.