Abstract
THE Transactions of the Croydon Natural History and Scientific Society for 1915, a copy of which has just reached us, contain a particularly good paper by Mr. G. M. Davies on the rocks and minerals of the Croydon regional survey area. The paper runs to 44 pages, and includes a careful series of analyses of rock-specimens from the Weald Clay and all the more recent formations. Reference is made to the discovery of the Marsupites-zone of the chalk at Russell Hill, Purley, and to the decomposition of marcasite, which gives rise to the soft masses of hydrated iron oxide (“red ochre”) so frequent in the chalk. A few sarsens are noted as occurring in the neighbourhood. Granules and. grains of zinc-blende and galena are noted as occurring in fuller's-earth at Redhill and Nutfield. The number of minerals found in residues is somewhat surprising, and a complete list is given. The regional survey, under the direction of Mr. C. C. Fagg, shows satisfactory progress, and in, connection with it Baldwin Latham has prepared a. map showing the site of the five Bournes which flow in the area.
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The Croydon Natural History Society. Nature 97, 473 (1916). https://doi.org/10.1038/097473a0
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DOI: https://doi.org/10.1038/097473a0