The Chalk outcrops across large parts of southern and eastern England and forms a significant number of the major physiographical features. Whilst it has been postulated that a chalk cover was laid down across just about all of England and Wales during Cretaceous times, subsequent uplift and erosion has resulted in it remaining only southeast of a line drawn roughly between The Wash and Lyme Bay in Dorset and eastwards from the scarps of the Lincolnshire and Yorkshire Wolds. Gentle folding of the Mesozoic rocks of this region during the Alpine orogeny has produced the London Basin and the Weald-Artois Anticline, the Hampshire Basin and the less gentle Purbeck-Wight monocline.