Читать книгу Walks in Silverdale and Arnside. 21 easy walks exploring the AONB онлайн

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Hollows formed by large pockets of melting ice or slow drainage are typical of limestone scenery. These hollows are called dolines, and sometimes have a water sink at the base. Hawes Water lies over several merged dolines, and the doline hollow in Deepdale is the result of a collapsed cave. The larger basins, such as the area now covered by Hale Moss, were once lakes and still flood in winter and in wet weather. The edges of the basins were sometimes lined by small cliffs, like the ones close to the road at the edge of Hale Moss. These cliffs are riddled with small tubular water-worn passages. There is evidence of several sea levels along the Silverdale coast, and there is an almost perfect circular phreatic tube cave worn by water pressure action.

The many limestone pavements in the area were scraped by ice and eroded by water and rainfall into their present form of clints – smooth surface blocks eroded over time – and grykes – the deep fissures between the clints. Solution pockets of varying sizes can also be seen on the surface where rainwater has created hollows by dissolving the limestone. Where the pavements are tilted, surface runnels are formed by water. These are especially pronounced on Farleton Fell and Hutton Roof Crags, where the rounded rundkarren are among the best examples in Britain. These were formed when the rocks were covered by a layer of vegetation and water draining away underneath the vegetation wore the limestone into its present attractive patterns. Sharp-edged rinnenkarren were formed where the rocks were open to erosion directly by the elements. These are rare in Britain and are best seen at The Rakes of Hutton Roof Crags.