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Hollingworth, S.E. and Taylor, J.H. (1951). The Northampton Sand Ironstone, Stratigraphy, Structure and Reserves. London: Geological Survey. British Geological Survey.
Jukes-Brown, A.J. (1904). The Cretaceous Rocks of Britain. Memoir of the Geological Survey of the United Kingdom. London: HMSO, 326pp. + 5 plates. British Geological Survey.