A large part of the Wealden in southern England does not contain ostracods, mollusks, or vertebrates, but has been found to contain fossil plant microspores and megaspores. These are now used to delineate stage boundaries and to correlate the stages with the lower Cretaceous succession in Lincolnshire and the Netherlands. The boundaries of the Berriasian, Valanginian, Hauterivian, Barremian, and Aptian are discussed, though not necessarily firmly located, and the point is made that much more work needs to be done.

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