Writing the chapter on the geology of Northumbria, it’s apparent that the reaction of 19th-century geologists against ideas of catastrophism went far too far. Yes, many processes occur constantly and gradually, but the history of the earth in general and Northumbria in particular is punctuated by catastrophic events: most recently the tsunami unleashed by the Storegga Slides, when huge sections of the continental shelf off Norway slid into the abyssal depths and set off giant waves down the east coast of Britain in 6100BC.