WAR-TIME LIMING IN ESSEX. 241 Schiller, J. 1929. Neue Chryso-und Cryptomonaden aus Altwassem der Donau bei Wien. Archiv. f. Protistenkunde, Vol. LXVI. Scourfeld, D.J. 1911. The use of the Centrifuge in Pond-life work. Journ. Quekett Microscopical Club. Ser. 2, Vol. XI. -------------. 1930. Nannoplankton and its collection by means of the Centrifuge. Watson's Microscope Record, No. 21. -------------. 1943. The rare spiral Diatom Cylindrotheca gracilis and its occur- rence in Epping Forest. Essex Naturalist, Vol. XXVII. Van Goor, 1925. Ueber einige bemerkenswerten Flagellaten der holliindischen Gewasser. Recueil Trav. Bot. Neerlandais. Tom. 22. WAR-TIME LIMING IN ESSEX. By RUPERT COLES, B.A., M.Sc. (Econ.), M.Sc. (Agric), Ph. D. [Read 30th January, 1943] MEMBERS of the Essex Field Club can no doubt recall papers in earlier numbers of the Essex Naturalist where attention has been drawn to the decline of arable farming in certain districts of the county. Reference in one paper is made to a survey submitted by Mr. Hunter Pringle in a Blue Book of 1894, in which he draws attention to the way in which the area stretching from the Dengie Hundred south-westwards to the Thames side was tumbling down to grass.1 The author of this report gives his views on the reasons for the location of the decline of arable farming in this particular district. He describes it as "three-horse land" when comparing it with the "two-horse land" farther north and west. This nomenclature is, of course, based on the differing soil types in the two areas—the heavy London Clay area in the south-east belt and the lighter Chalky Boulder Clay running north and north-west of this belt. These differences in soil-texture necessitated the use of a heavy team on the stiff London Clay, whilst the lighter Chalky Boulder Clay needed only a two-horse team for ploughing. Throughout the history of Essex these two major soil areas have strongly influenced settlement and agriculture. The early English settlements show a continual striving to settle and cultivate the north-western heavily wooded belt with its more fertile and easier working soils of the Boulder-Clay district.2 The present writer has endeavoured to trace their movements in various papers he has read before the Club and he concludes that by the 16th century arable farming was firmly established 1 Blue Book. B.P.P., 1894, Vol. xvi. See also Essex Naturalist, Vol. xxvi., pp. 22, 23. 2 Essex Naturalist, Vol. xxiv., pp. 115-133, Vol. xxvi., pp. 204-220.