Page:A Treatise on Geology, volume 1.djvu/271

 CHAP. VI.

In the basin of London, the series is less complete. Mr. Prestwich has determined the place of the London clay in the series to be below the Bagshot sand, and on the parallel of the Bognor beds. (GeoL Proc. 1847.) Hence the following general section:—

In Essex, Suffolk, and Norfolk, the plastic clay group is chiefly represented by the lower green sandy portions, which appear seldom deficient (being found in the Isle of Wight, at Reading, Woolwich, Sudbury, &c). The London clay is seen at Harwich; and a superior marine deposit, the " Crag, " unknown elsewhere in England, appears at Ramsholt, Orford, &c. in two divisions, while a third is added above in the vicinity of Norwich. Thus we have:—

Lower or coralline crag, less ochraceous, almost without pebbles; containing abundance of shells not at all