River Cober

A common belief is that until the 13th century the River Cober ran directly to sea, until its mouth became blocked by a deposition of sand which formed Loe Bar and created Loe Pool. Loe Bar was most likely created by eustatic sea level rise after the last ice age. The rising sea level pushed a large amount of sediment into the mouth of the river, blocking it and creating a barrier beach. Loe Bar consists mainly of flint, a rock not found in Cornwall; the nearest onshore source is in east Devon, 120 mi away. The Helston branch railway (which closed in 1962) ran along part of the valley into Helston. The Railway line crosses the main River on the 5-arch Cober Viaduct.