IN THE ISLE OP PORTLAND AND AROUND WEYMOUTH. 35 the beach to the northward, we find it passes under a light-coloured loam with seams of angular debris, succeeded by a mass of angular debris, chiefly of the local rocks (fig. 2). On the east cliff the relation of the several deposits is not well shown. Still the order of succession is sufficiently apparent, and near the Sand-holes the section is as under (fig. 3). Fig. 3. — Raised Beach, with overlying angular land-debris, ham, and sand, near the Sand-holes, east side of Portland Bill. d. Angular rock-debris, 5 feet i! d'. Loam with land-shells and j -vfe^^^J^S layers of angular debris, < ""^^ 6 feet I e'. Sand, If foot e. Raised beach, 3i feet Cliff of Portland Rocks, upper surface waterworn. Level of present beach. It is, however, on the west cliff that the finest section is exposed. Proceeding north-westward from the Bill, the beach is seen to pass under the loam with the overlying rubble-bed before mentioned. The loam varies in thickness from 10 feet at the northern end, to nought at its southern end, and contains subordinate seams of the same angular debris, giving it an appearance of rough stratification. In this loam I found, in places, seams containing considerable numbers of land and freshwater shells, but only of the few following species (determined, with the others, by Mr. Gwyn Jeffreys) : — 1. Limnaaa peregra, Miiller. 2. truncatula, Midi., var. spira producta. 3. Li max agrestis, Linne (shields). 4. Succinea oblonga, Draparnaud. 5. Pupa marginata, Drap. I found only one small fragment of bone, and derived (Jurassic?) specimens of a species of Gyihere. But the most interesting part of the section is that exposed just beyond the point to which the quarrying has been carried, and where the beach ends by the side of a large fissure which runs inwards from the shore. On the surface there is nothing to indicate any change, the ground continuing its gradual slight slope from north to south. Descending, d2
Page:Quarterly Journal of the Geological Society of London, vol. 31.djvu/81
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IN THE ISLE OF PORTLAND AND AROUND WEYMOUTH.
35