Carbonate platform rocks are present in Nye, Lincoln, Elko, Eureka, Lander, White Pine, Esmeralda, and Clark Counties. This unit is primarily Ordovician in age but does include Upper Cambrian rocks at the base (Page, Lundstrom, and others, 2005). The Pogonip Group, including the Antelope Valley Limestone is the most common name used. In Clark County it also includes the Ely Springs Dolomite, and includes the Eureka Quartzite in White Pine and Clark Counties. Unit OCc corresponds to depositional sequence 2 of Cook and Corboy (2004). Where Ocq is mapped separately, it overlies OCc. Otherwise OCc is depositional under SOc, or in southern Nye and Clark Counties, it is overlain directly by DSc where SOc is not differentiated. Unit OCc depositionally overlies unit Cc.