Most of the valley bottoms throughout Swaledale contain thick deposits of glacial and debris-flow diamictons, glaciofluvial sand and gravel and coarse-grained river gravels, although in the upper part of Skeb Skeugh fine-grained lake peats and marls fill the valley bottom. In some places the valley bottoms are undergoing active incision and waterfalls reflect the differences in rock hardness.
The large-scale landforms of the area are visually impressive and geomorphologically intriguing. The Swale valley crosses the region from northwest to southeast but takes a sharp right-angle bend at Hartlakes. However, a valley of a similar size to the Swale, but with a tiny stream called Skeb Skeugh, extends south of Keld towards Thwaite, then bends sharply towards the east to rejoin the valley of the Swale just beyond Muker. Between these valleys, Kisdon forms an isolated hill some 200m above the valley bottoms. The origin of Kisdon Hill, the changing direction of the Swale valley and the virtually dry valley of Skeb Skeugh have long been a topic of debate.