BOTANY scene of Borrer's labours and those of Mr. W. Mitten of Hurstpierpoint, who contributed the Hst of flowering plants to Mr. Merrifield's Sketch of' the Natural History of Brighton. The Ouse district has been well in- vestigated by Mr. J. H. A. Jenner, Mr. W. C. Unwin and the members of the Lewes and East Sussex Natural History Society. In his Flora of Eastbourne Mr. F. C. S. Roper published an excellent account of that of the Cuckmere. The Rev. E. N. Bloomfield of Guestling, in his Natural History of Hastings and St. Leonards, with supplements in 1883 and 1888, has supplied a good catalogue of the plants of the East Rother, and for the Medway district we have Mr. E. Jenner's Flora of T'unbridge Wells and its Neighbourhood., with lists by the Rev. W. H. Coleman, Dr. Deakin, Dr. de Crespigny and other botanists. Before considering our flora however, as it now presents itself to us, it will be well briefly to examine its origin — a very interesting subject — and this can only be done in connection with a wider one, that of the origin of the plants of Great Britain and the geographical distribu- tion of our British plants which can merely be glanced at here. That this island once formed part of an adjacent continent is now generally admitted. Its separation must have been gradual, and along the south coast we still find this constantly enlarged by the action of the sea. A thorough examination of the fossil plants of Sussex is still a desideratum. Those of the earlier geological periods have mostly perished from the intense cold which accompanied glaciation. Mr. Clement Reid, who has studied the plants of the latest Pliocene deposit, and the flora of various deposits from that ancient period to the time of the Roman occupation, has, by collecting the seeds and seed vessels of numerous species, shown that a considerable number of the plants we still meet with existed in prehistoric times. With respect to submerged forests he tells us that the newest he examined dates fully 3,000 years since. In Sussex one of these existed at Selsey, whence huge portions of trees are occa- sionally obtained, and at Hastings there was a submarine forest which contained the yew, oak and pine. The geology of the county being treated of elsewhere, it is only pertinent to remember that its strata belong mainly to the Secondary formations. The Tertiary beds appear chiefly on the coast in its south- west extremity, and strips of these, chalk, greensand, and the sandstone of the Wealden formations, are its principal features. The range of chalk downs in Sussex is more than fifty miles long, with an average breadth of four miles and a half and an average altitude of about 500 feet, rising to between 800 and 900 feet eastwards. The ridge of the Weald attains its greatest height at Crowborough Beacon, where it is more than 800 feet above the level of the sea. The coast line has an extent of about ninety miles. With respect to the districts hereafter to be considered, five of them are physically very similar, each having a portion of coast and down and weald, whilst that towards the eastern extremity is altogether on the Wealden formation, extending also to the coast, and the seventh occupying the northern slope of the Wealden ridge has no seaboard. 43
