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 



