A HISTORY OF ESSEX Most of the shells appear to have belonged to animals which lived on the spot : they do not bear evidence of having been shifted and rolled as in later stages of the Red Crag. The Crag at Little Oakley is regarded by Mr. Harmer as a slightly newer stage than that at Walton. He has lately reopened the pit at Beaumont and obtained a fine series of fossils. Occupying such small areas the Crag has no particular influence on the scenery and very little on the soils. As a rule the land is fertile, and the deposit itself when very shelly has been dug for marling ground deficient in lime. The Pliocene period affords evidence of temperate conditions which were slowly changing towards the more rigorous climate of the Pleisto- cene. At the close of the period England was still united across the Straits of Dover with the continent. 1 There are several tracts of pebbly gravel in Essex, some mainly derived from the old Bagshot pebble-beds as at High Beech, near Brent- wood, Langdon Hill and Hadleigh, some derived probably from earlier Eocene pebble-beds. These are most largely formed of pebbles of flint and quartz, and in this respect they differ from the more mixed gravels of the other high grounds, which contain quartzites, various igneous rocks, and likewise fossils derived from many older formations, and which are definitely connected with the Glacial period. Some patches of pebbly gravel seen in the clifF at Walton-on-the- Naze, also near Marks Tey, Witham, Braintree and Thaxted, and near Epping, have been regarded as Westleton Beds by Prestwich, 2 who took the name from the village of Westleton in Suffolk, and regarded the beds as the base of the Glacial series. The age of the Westleton Beds of Westleton is not undisputed : they may belong to the Glacial period. 3 Hence it will be best not to attempt any full discussion of this vexed question, but to be content here to remark that as Prof. T. M'K. Hughes, S. V. Wood, jun., Prestwich, Mr. Whitaker and others have pointed out there may be gravels of Pliocene (or Pre-Glacial) age which were spread over the country and partially denuded prior to the great glaciation which came about in later times. To S. V. Wood, jun., we are particularly indebted for a knowledge of the Drift deposits of East Anglia. He was the first to commence their detailed and systematic study in Essex, and in 1867 he presented to the Geological Society copies of the Ordnance Sheets i and 2 (Old Series) on which he had surveyed the geology including the various superficial deposits. The maps were accompanied by a MS. Memoir on the Structure of the Glacial and Post- Glacial Beds in southern Essex. 1 See Reid, Origin of the British Flora, pp. 34, etc. 2 Quart. Journ. Geol. Soc., vol. xlvi. pp. 128, 162, etc., and Geol. Mag., 1898, p. 404 ; Monckton and Herries, Free. Geol. Assoc., vol. xi. p. 18 and p. Ixv. and vol. xii. p. 108 (where further references are given). 3 H. B. Woodward, Geol. Mag., 1882, p. 452 ; and Geol. England and Wales, ed. 2, p. 505. 12
