The beds of lignite which have been mined sporadically since the early 16th century, were formed in the bed of an ancient lake, which was mined by opencast methods.
- Pengelly, W. & Heer, O. On the lignite formation of Bovey Tracey, Devonshire (Nabu Press, 2010). Reprint from Philosophical Transactions, Part II, 1862.
- Devon County Council Website