Nidderdale is at about the same altitude as Wharfedale and separated by just one ridge including the summit of Great Whernside. The Great Scar limestone so evident in Wharfedale is nowhere to be seen in Nidderdale as the easterly dip of the Pennine anticline carries it well below the floor of this small valley. The limestone visible in Nidderdale is the Yoredale series, and almost all the cave system has developed within the narrow band (maximum of 40m) of the Middle Limestone. The limestone outcrops in three inliers: one to the north including the cave sinks of Manchester Hole and Goyden pot, one small outcrop about 300m further south including New Goyden pot, and one nearly 2 km further south including the Nidd Head resurgences. The most northern inlier of limestone is cut off from the limestone beds at Scar House Reservoir by a large fault. The most southern inlier of limestone is cut off from any continuation by a fault just north of the head of Gouthwaite Reservoir. Each inlier is separated on the surface by the base of the Grassington Grit.