1. Geological Survey Map, Sheets 19 and 20.
2. Pooley Giles.—“Lapis Calaminaris.” ‘Phil. Trans.,’, Vol. xvii, p. 672.
3. Maton, W. G.—“Observations relative chiefly to the Natural History, etc., of the Western Counties of England,” 2 Vols., 8vo., Salisbury. [‘Notes on Lead and Zinc Mines,’ etc., Vol. ii, pp. 127, etc.]
4. Observations on the South-Western Coal District of England;Buckland;Trans. Geol. Soc.,1824
5. Weaver, Thomas.—“Geological Observations on part of Gloucestershire and Somersetshire.” ‘Trans. Geol. Soc.,’ Ser. 2, Vol. i, p. 317.