The hummocky terrain in the middle-distance is a field of drumlins: small hills of boulder clay formed during the last Ice Age by flowing glaciers dropping sediment. At a very different scale, this is analogous to rippled sand deposits in the bed of a river, and in the same way, all the drumlins are aligned with the direction of ice flow (southward down Ribblesdale; forming Ribblesdale, in fact), steeper on the upstream side, shallower on the lee slope.