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Published online by Cambridge University Press: 14 March 2018
1 S. G. Perceval, Geol. Mag., 1866, vol. 3, p. 377.
2 Idem, ibid., p. 518.
3 For details and a plan see O. T. Jones, Lead and zinc: The mining district of North Cardiganshire and West Montgomeryshire. Mem. Geol. Survey: Spec. Rep. Mineral Resources of Gt. Britain, vol. 20, pp. 120-126 (1922).
4 The figures are National Grid References in square SN.