River Mole in 1613. In John Speed's 1611 map of Surrey this stretch of the river is denoted by a series of hills accompanied by the legend "The river runneth under". However the river's name is unlikely to have derived from this behaviour: The "Oxford Dictionary of English Place Names" suggests that "Mole" either comes from the Latin "mola" (a mill) or is a back-formation from "Molesey" (Mul's island). In John Rocque's 1768 map of Surrey, the name "Moulsey River" is used. In common with much of the rest of the Weald, the earliest evidence of human settlement along the Upper Mole
Sutton and Mole Valley lines the landowner, Thomas Grissell, meant that vertical ventillation shafts could not be constructed and the tunnel portals were given lavish architectural treatment. Betchworth Tunnel is south of Dorking. It is long with a maximum gradient of 1 in 80 (1.25 per cent). It runs through the upper greensand of the Deepdene Ridge to the east of the town. Construction difficulties delayed the opening south of Dorking. It collapsed on 27 July 1887, remaining closed for over six months. Sutton and Mole Valley lines The Sutton and Mole Valley lines were constructed between 1847 and 1868 by the London, Brighton and