The most commonly outcropping pre-rift sequence is Carboniferous sedimentary rock ranging in age from Mississippian to Pennsylvanian. Here we see red Pennsylvanian Riversdale Group clastics (right) unconformably overlain by a very thin veneer of coarse clastics of Blomidon Formation (white), in turn overlain by North Mountain basalt (center and left) at Wasson Bluff.