The landscape owes much to the underlying Triassic "bunter" formations. These are sandstone deposits containing rounded pebbles. They can be found in Warwickshire, Cheshire, Staffordshire, Nottinghamshire, Yorkshire, Devon and Dorset in England. They are thought to be alluvial deposits. Judging from the rounding of the mainly quartzite pebbles, they were carried for a long time in a large and turbulent river. The hard pebbles got powerful abrasion. The deposits in the English Midlands are thought to have been carried northwards from Brittany in northern France.