Regression caused a nearshore quartzose carbonate facies to shift to the edge of the carbonate shelf. Transgression followed. Seaward of the unconformity produced by regression, a dolomite formed on the inner slope of a silled outer shelf basin. This dolomite is here named the Sadler Ranch Formation. The dolomite front forms the facies boundary between the Sadler Ranch and the upper Coils Creek Limestone, which was deposited in the shallow outer shelf basin. Conodonts date the regression as serotinus Zone and the subsequent transgression as spanning the upper part of the serotinus Zone, the patulus Zone, and the lower part of the costatus costatus Zone. The transgression correlates closely with the Onondaga Limestone of New York and the Couvinian-Eifelian of western Europe and is of probable eustatic origin.--Modified journal abstract.