thank you to the following for information / help

Alan Eaves - Forestry Commission Area Forester, Dartmoor/Plym

Mark Brayshay - Geography, University of Plymouth

Steve Roberts - Plymouth Mineral & Mining Club

Flea Palmer - LSA team, University of Plymouth

references / further reading

Plymouth River - Crispin Gill - Devon Books - 1997

Dartmoor, A New Study - Crispin Gill - David & Charles 1970

Plym Valley Railway Handbook no.1 - Bernard Mills 1991

The Tavistock Launceston and Princetown Railways
- G.H. Antony - Oakwood Press 1971

The Plymouth Tavistock and Launceston Railway
A.R. Kingdom - Ark Publications 1990

Mines of Dartmoor - Vol 1
A.K. Hamilton Jenkin - David & Charles 1974