Chevron folding at Millook Haven in Cornwall, England. The rocks here are of the Upper Carboniferous Crackington Formation. They are characterised by shales and thin turbidite sandstones. Turbidites are deep marine sediments originating at the continental shelf, drawn down to ocean basins by turbidity currents. The folds were formed in the late Devonian during the late stages of the Variscan Orogeny (continental collision): as the basin was compressed by the colliding continents, the strata were intensely folded, producing the dramatic folding visible here. A recent rockfall is visible at the cliff base.