58 LONDON DISTRICT. 



80 ft. in 20 miles. Before the river was able to widen or grade 

 its valley deposition of gravel began, and the deep channel was 

 filled up practically to the level of the Upper Flood -plain.' 

 Hence gravels laid down before or after the cutting of the deep 

 channel cannot be distinguished except where a series of borings 

 has revealed the form of the cross-section of the base, and the 

 term ' Low Terrace ' or Flood-plain gravels must cover both. 



Between Staines and Brentford a band of Low Terrace 

 gravels with patches of overlying brickearth is found between 

 the lower margin of the Middle Terrace and the river except at 

 Hampton, where that line touches the river. These beds are 

 probably for the most part older than the buried channel ; remains 

 of reindeer are very common, together with many species found 

 also in the Middle Terrace (e.g., the hyena, bison, wild boar) ; 

 the reindeer and saiga antelope appear to be new arrivals. Most 

 of them have been recorded from Twickenham, 1 the last named 

 there only ; a few plant remains were also found. 



Another important area of Low Terrace deposits extends 

 from Brentford to Westminster and runs up as far north as 

 Wormwood Scrubbs between the higher ground of Acton and 

 Holland Park. Many mammals and molluscs, including among 

 the latter the extinct fresh -water mussel Unio littoralis, have 

 been found a little north of Kew Bridge. The ' island ' of gravel 

 and sand on which Westminster was founded Thorney Island 

 belongs to the Flood-plain, as do all the eyots on which the 

 ancient hamlets around London, such as Chelsea, Battersea and 

 Bermondsey, were built. At the Admiralty Buildings Mr. Lewis 

 Abbott found a large number of fossils, both mammals and 

 molluscs, as well as the plant-bed with arctic birch; he noted 

 that in the basal bed, ' large boulders forming a layer, had been 

 driven into the London Clay and all their tops planed off and 

 striated.' 2 



It is from deposits of this age in the Lea Valley that most of 

 our knowledge of the period is derived ; they extend along the 

 west bank of the river throughout our area, and several large 

 pits have been opened in the gravel. In certain of them at 

 Ponder's End and Angel Road Mr. Hazzledine Warren discovered 

 a peaty bed containing plants, mollusca, etc., indicative of a 

 cold climate about equivalent to that of Lapland to-day. 3 The 

 date of the deposit appears to be very late in the palaeolithic 

 sequence, considerably later than that of the Admiralty bed. 

 It may be that the ' Buried Channel ' stage intervenes, and that 

 these two arctic beds belong to the Lower and Upper Flood -plain 

 gravels respectively, but ' without further evidence one could 

 not,' as Mr. Warren remarks, ' suggest two separate arctic stages 

 so near together as that of the Admiralty Buildings and Ponder's 



iLeesou, J. B., and G. B. Laffan, Quart. Journ. Geol. Soc., vol. 1, 1894, 

 pp. 453-462. 



2 Proc. Geol. Assoc., vol. xii, 1892, pp. 346-356. 



3 ' Late Glacial Stage in the Lea Valley,' Quart. Journ. Geol. Soc., vol. Ixviii, 

 1912, pp. 213-228, seven appendices and 3 plates. 



