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The Craven Fault

The Craven Fault is a series of geological fault lines (including North, Mid and South Craven Faults) along the southern and western edges of the Yorkshire Dales National Park. It is formed at the underlying boundary of the Askrigg Block.

At its surface, the Fault generally defines a boundary between the limestone uplands of the higher Dales and gentler scenery to the south and west. It features some spectacular limestone formations, including the geological unconformity and waterfall at Thornton Force near Ingleton, with similar examples at Clapham and Austwick. Further along its lines, limestone features can be seen at Feizor and Giggleswick Scar, Attermire Scar near Settle, Malham Cove and Gordale Scar near Malham in Malhamdale, Linton Falls in lower Wharfedale and the sinister gorge of Trollers Gill above Skyredale, near the surface termination of the fault at the Skyreholme Anticline.

At several points along the southern edge of the Fault are ranges of reef knolls - limestone hills formed as coral atols in the warm, shallow waters of ancient prehistoric seas. Fine examples of these limestone reef knolls can be seen on the moors above Settle and in the southern part of Malhamdale and at the five Cracoe Reef Knolls, which lie between the twin villages of Rylstone-Cracoe and Burnsall, in the so-called Barden Triangle. Fine views of the latter, in different seasons and weather, may be had from the west of Hebden.

Charles Darwin mentions the Fault in On the Origin of Species, ch. IX, "On the Imperfection of the Geological Record", regarding the planing-down action of ancient seas on great geological displacements: "The Craven Fault, for instance, extends for upwards of 30 miles, and along this line the vertical displacement of the strata has varied from 600 to 3000 feet."

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