Page:VCH Suffolk 1.djvu/85

 BOTANY' jA S the Flora of a county is, in a great measure, dependent upon /% its geological formation and physical conditions, a brief sum- / % mary of these features of the county of Suffolk seems a necessary preface to an account of its botanical productions. Chalk, forms the foundation of the whole county, with the possible exception of certain tracts beneath the Fenland west of Mildenhall, where the underlying Gault and Kimmeridge Clay may possibly come to the surface. South of a line (roughly) drawn between Sudbury and Aldeburgh the chalk is covered by Eocene deposits, consisting of Thanet Sands, Reading Beds, and London Clay, the last-mentioned being the most important ; these beds, however, are in their turn covered (partially in the south-east part of the county and wholly in the north-east) by the later Pliocene (Crag) deposits, peculiar to the counties of Essex, Suffolk, and Norfolk. The oldest, the Coralline Crag, consisting of a light yellow calcareous deposit with a little sand, is found in an isolated area between Aldeburgh and Boyton and near Shottisham. The later Red Crag occurs in the south-east part of the county and consists of shelly sands coloured red by oxide of iron, hence the name. In the north-east are found the variable group of sands, laminated clays, and pebbly gravels which make up the Norwich Crag. All these strata, however, are covered for the most part by Boulder Clay, brick earth, sand, and gravel belonging to the Pleistocene Period, and mainly glacial in origin. The Boulder Clay, the most important of the group, consists chiefly of stiff chalky and stony bluish-gray clay and occupies a considerable area in central, or (as it is locally termed) ' High ' Suffolk. More than two-thirds of the county consists of heavy land ; richer districts occur between the Orwell and the Stour, the extreme north-east of the county, and the country between Hopton, Euston, and New- market. Light sandy soils are found in the north-west — a tract known as the Breck District, the most interesting part of the whole county botanically, and fully dealt with under Division I — and again in the extreme east, many species of plants occurring only in the county in these two districts. ' In the preparation of the Phanerogamic portion of this article the following gentlemen kindly assisted in various ways, and thanb are due to them : — Messrs. A. Bennett, Rev. G. R. Bullock-Webster (Characes), W. A. Dutt, Rev. E. N. Bloomfield, Rev J D. Gray, Rev. W. M. Rogers. 47