BOTANY its water is loaded with a sufficient percentage of chloride of sodium to exert a considerable influence upon the surrounding vegetation, so that several maritime or sub-maritime plants occur in this inland situation. They are the sea sandwort (Buda marina), the sea club-rush (Scirpus mari- timus), a rush (Juncus Gerardi], a sedge (Carex distant], he celery (Apium graveolens), the water dropwort ((Enanthe Lacbenalii], and a horned pond- weed (Xannichellia maritima], the X.pedunculata, Reichb., of my Berkshire Flora. In addition to these there are forms of Atriplex deltoidea and of Agrostis alba, which resemble the marine forms of these plants. THE PORTLAND BEDS exist only as a small outlier on which the village of Bourton is built, and the formation does not exhibit any special plants. THE LOWER GREENSAND occupies a much less continuous belt than the formations already alluded to, as in places it is overlapped by the gault. The outlier of Boar's Hill, where it reaches its highest point in the county of 535 feet on Pickett's Heath, Faringdon Clumps and Badbury Hill in the west of the county are capped by the formation, and there are some picturesque cliffs of it at Clifton Hampden. These detached areas of the Lower Greensand form a light sandy soil, and offer a home for many interesting and local species. The bramble flora especially is as rich as it is poor on the Oxford Clay and Gault. The crimson poppy (Papaver hybnduni), the pink (Tunica prolifera), the English catchfly (Silene anglicd), the sheep's scabious (Jasione montand), the heaths Galluna and Erica cinerea, the climbing bindweed (Polygonum dumetorum) and many other species are found on it. The Lower Greensand contrasts very markedly in the character of the scenery from that of the Oxford Clay and Gault, which is further accentuated by the fact that the flora itself is so very different in appearance. THE GAULT forms another zonal band, i to 3 miles in width, across the county, and consists of a blue clay which is usually calcareous and often micaceous. It forms a stiff, heavy and rather cold soil, which were it not for a few deposits of drift would be a singularly undiversified country, either as regards its scenery or its vegetation. The sparsity of woodland is an especially noticeable feature, and accounts for the absence of many sylvan species from the district. The ragwort (Senecio tenuiflorus) is a conspicuous plant, and the willow herb (Epilobium tetragonunf), and a hybrid of this with E. parviflorum occur. The marshy meadows afford the orchid (Orchis incarnata) and the bogbean (Menyanthes trifoliate?) . THE UPPER GREENSAND occupies a belt which narrows, from 5 or 6 miles at Wittenham, till it almost thins out at Woolstone, and forms a steep terraced escarpment to the south of the Gault plain. The upper part is calcareous, and also contains occasionally phosphatic matter ; therefore the soil is very fertile, which is further increased by the supply of marly debris which every shower washes down from the chalk escarpment and spreads over its surface. The flora is consequently much more varied than that of the Gault. About twenty miles south 43
