Geodiversity Landscapes: Fen Islands and Ridges

Within and on the edge of the fenland are a number of islands and ridges, each with a different geological character, and some with a very rich cultural history due to their isolated location in what was the largest area of wetland in the country. There are five main islands – Whittlesey, March, Chatteris, Stonea and the Isle of Ely, and two ridges – Yaxley Ridge and Upware Ridge. The first four islands are partly formed by the March Gravels, probably deposited during a cold stage of the Pleistocene but with reworked material from a warmer phase and elements of coastal deposition. The Isle of Ely is formed mostly from clay and sandstone ridges and includes North Hill, the highest spot in the Cambridgeshire Fens. All but Whittlesey have glacial till or other glacial material that gives them extra height. The Yaxley Ridge is mostly formed from glacial material whilst the Upware Ridge has a unique outcrop of Corallian (Upper Jurassic) limestone – you can still see the corals!