Description: Looking south downstream, with the base of Thorpe Cloud on the left. The River Dove (from the old British word dubo meaning dark) seen here, rises on the high moorlands of Axe Edge and its clear waters run southwards for 45 miles to join the River Trent. Around 350 million years ago, the whole of what is now the Peak District was covered with a shallow tropical sea, with deep lagoons fringed by coral reefs. The fossilised remains of sea creatures and corals make up the limestone which forms much of what is now Dove Valley. At the end of each of the Ice Ages (during the last 2 million years), vast quantities of melting water, carrying rock debris, cut through the layers of limestone to produce the steep and craggy gorges of the Dales. Some of the limestone formed very hard reefs - these were left standing as hills and peaks while the less resistant rocks around were worn down by erosion of wind and water. Dovedale was made famous by Izaak Walton and Charles Cotton who wrote The Compleat Angler in the 17th century. The fishing lodge they used is still standing (but not open to the public). In the 18th century and later, a popular summer activity with visiting gentry was to visit the beauty spots of Dovedale and Ilam. As road transport improved and the arrival of the railways brought easier travel, Dovedale continued to grow in popularity with visitors. Many of the weirs across the river were built to increase the feeding area for trout and so improve the fishing. The river also powered several mills. The conservation value of the Dove Valley was recognised by the National Trust through its acquisition of the South Peak Estate, much of which lies in Dovedale and Wolfscote Dale. Dovedale was proposed as a separate National Park in the 1930s. It was eventually included within the Peak District National Park when it became Britain's first National Park in 1951.