River Otter, Devon River Otter, Devon The River Otter rises in the Blackdown Hills just inside the county of Somerset, England near Otterford, then flows south for some 32 km through East Devon to the English Channel at the western end of Lyme Bay, part of the Jurassic Coast, a UNESCO World Heritage Site. The Permian and Triassic sandstone aquifer in the Otter Valley is one of Devon's largest groundwater sources, supplying drinking water to 200,000 people. The river's source is north of Otterford, where a stream feeds the Otterhead Lakes: and then through Churchstanton before entering Devon. The river flows through a
Geology of Dorset Geology of Dorset Dorset (or archaically, Dorsetshire) is a county in South West England on the English Channel coast. Covering an area of ; it borders Devon to the west, Somerset to the north-west, Wiltshire to the north-east, and Hampshire to the east. The great variation in its landscape owes much to the underlying geology which includes an almost unbroken sequence of rocks from 200 Ma to 40 Ma and superficial deposits from 2 Ma to the present. In general the oldest rocks (Early Jurassic) appear in the far west of the county, with the most recent (Eocene) in the