Zoom out from one of the Norber erratics, one of the finest groups of glacial erratic boulders in Britain, on the southern slopes of Ingleborough near Austwick in the Yorkshire Dales, England, UK. The boulders are old greywacke deposited on limestone by the melting ice sheets at the end of the last glacial period some 12,000 years ago. The boulders protect the underlying limestone from erosion while the limestone around them is eroded, leaving them perched on pedestals.