In north-east Cornwall, between Boscastle and Widemouth, the spectacular cliff section exposes the contorted dark grey shales and thin sandstones of the Crackington Formation. This thick sequence of rocks, which forms part of the so-called Culm Measures of North Cornwall and North Devon, was deposited in a relatively deep sea basin. The muds that now form the slates were deposited on the floor of the basin, which was occasionally disturbed by currents of muddy water carrying sands and pebbles that swept down the flanks of the basin.

These so-called turbidity currents and the deposits they produced may represent the product of earthquakes which disturbed unstable sediments on the submarine slopes flanking the basin. The entire Carboniferous succession within Cornwall was subjected to intense compressive forces and heat during a period of mountain-building at the end of the Carboniferous and into the early Permian (290-248 million years ago) which has resulted in the spectacular folding and faulting of the Carboniferous strata. The 100 metre high cliff at Bridwell Point is used to illustrate fold structures in many geology textbooks. The principal interest of this site lies in the flatlying chevron folds which are superbly exposed in the cliffs and have been studied in great detail. At Boscastle, the accessible exposures superbly demonstrate the three-dimensional nature of refolded folds.