56 LONDON DISTRICT. 



undisturbed, well stratified, layers of sand and of loam occurring 

 with the gravel, though the latter is frequently very coarse, 

 especially towards the base. 



The Middle Terrace. After the deposition of the Upper 

 Terrace the river again began to deepen its bed, lowering the 

 level some 30 ft. before deposition was renewed, and the Middle 

 Terrace formed. This terrace occupies a larger area than the 

 upper and its gravels are accompanied by important deposits of 

 brickearth. 



In the Colne Valley it occurs at Denham and at Mill End, 

 where it contains implements. In the main valley it forms a 

 wide spread extending from West Drayton and Staines to Brent- 

 ford and Hampton ; its lower margin, concealed by the banking 

 of Low Terrace deposits near Staines, was revealed when the 

 reservoirs were built j 1 it is separated from them by outcrops 

 of London Clay at Hanworth Park, Hampton, Twickenham, and 

 between Isle worth and Brentford. Over the northern part of 

 this spread brickearth occurs, sometimes as much as 20 ft. thick ; 

 the deposit has been largely utilised and is almost worked out. 

 A good section of the gravels, some 20 ft. in height and yielding 

 implements, may be seen near Hanwell Railway Bridge. East 

 of the Brent this terrace is found at Baling and Acton, the lower 

 margin practically coinciding with the upper limit of the Low 

 Terrace Brickearth. Another large area stretches from Pad- 

 dington and Kensington to the Lea Valley. The lower limit 

 runs from Holland Park past the Albert Hall to Knightsbridge, 

 across the Green Park, along Jermyn Street, and thence to the 

 river bank at Charing Cross. The valley of the Fleet cuts 

 through the gravel, but the City is built on Middle Terrace 

 deposits, both gravel and brickearth, the latter having been 

 worked in Roman times. This gravel area has had a great 

 influence on the location and growth of London (p. 89). Many 

 important sections have been laid open at various times, notably 

 at the site of the Law Courts 2 and at Endsleigh Street, the latter 

 famous for its fossils 3 ; mammoth, horse and red deer were found 

 in the gravel, while at the base was a loam bed containing seeds ; 

 these were identified by Clement Reid, and all belong to species 

 now living in Middlesex; the period of cold climate can, there- 

 fore, hardly have begun. The Middle Terrace gravels of the Lea 

 form a band whose lower margin is about 1 mile west of the 

 river ; the sections at Stoke Newington and Clapton 4 are famous. 

 East of the Lea, deposits of this age extend from Wanstead 

 Flats to the margin of our area ; they include several patches of 

 brickearth overlying the gravel, notably that at Ilford, which 

 has yielded many fossils, including mammals and other vertebrates 

 and molluscs. 5 



1 ' Geology of Windsor and Chertsey ' (Mem. Geol. Surv.), 1915, p. 75. 

 2 Hudleston, W. H., Proc. Geol. Assoc., vol. iii, 1874, pp. 43-64. 



3 Quart. Journ. Qeol. Soc., vol. xlviii, 1892, pp. 453. 



4 Smith, W. G., * Man the Primeval Savage,' 1894, pp. 189-294. 



5 See Hinton, M. A. C., Proc. Geol. Assoc., vol. xvi, 1900, pp. 271-281 ; Ken- 

 nard, A. S., and B. B. Woodward, ibid., pp. 282-286. 



