Part of the terrain around Malham Tarn is extremely unusual. The area as a whole is underpinned by limestone and the lake itself is an uncommon marl (alkaline) lake. An area of fen and bog has developed since the last ice-age over a shallow area of the lake, gradually building up a dome of acid peat bog, now 10m thick in parts, that allows rare acid-loving plants and mosses to grow. It became a National Nature Reserve in 1992 and is now carefully managed to provide the right balance to support and nurture the plants, birds and other wildlife. Such bogs are an especially valuable resource as they store carbon that would otherwise contribute to global warming.
There are deer in the reserve and for a moment I thought I saw one... or perhaps a leopard? ... but no, just a piece of wood.