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 GEOLOGY elsewhere. As might be expected the deposits are of an estuarinc char- acter where they border the Thames, the wide mouths of the Crouch, Blackwater and Colne, and the inlets between Walton-on-the-Naze and Harwich. Scrobicularia plana and Tellina balthica occur in the tidal clays. 1 Along the left bank of the Lea there is a variable breadth of Allu- vium forming a succession of marshes. At Walthamstow during excav- ations for the filter-beds and reservoirs of the East London Waterworks Company in 186869, man y interesting remains were found and described by Dr. Henry Woodward. Besides numerous land and freshwater shells of existing species, many bones of mammalia and a few of birds and fishes were obtained. There were skulls and portions of skeletons of man, of prehistoric and later age, as well as implements of stone, bone, bronze and iron. There were remains of dog, fox, horse, wild boar, red deer, reindeer, roebuck, elk, urus and short-horned ox, also remains of beaver in considerable abundance. As remarked by Dr. Woodward, the work and enjoyment of the beaver is to construct dams, forming large deep and clear pools of water, with a series of small waterfalls at in- tervals. 8 From Felstead, Chignal St. James, Roxwell and other localities in Essex many land and freshwater mollusca have been obtained from shell- marl and other alluvial deposits. 8 Along the borders of the Thames valley many interesting sections have been recorded. Thus an excavation made in 1890 for a new gas- holder at Beckton, North Woolwich, showed the following strata : ft. in. {Soil i 6 Clay 26 Mud 14 o Peat 20 Mud 10 Valley Gravel. Ballast (gravel and sand) 200 Basement-bed of London Clay and Woolwich and Reading Beds. The peat yielded much wood, including bog-oak, while in the Alluvium down to a depth of twenty feet there were found human remains and bones of ox [Bos taurus, var. prim/genius and var. longifrons t red deer, wild boar, dolphin and whale. 4 In other localities remains of birch, alder, hazel and yew have been recognized. From the mouth of the Lea eastwards there is indeed a succession of 1 See F. C. J. Spurrell, On the Estuary of the Thames and itt Alluvium,' Prac. Ceo/. Attec., roL xi. p. 210 ; H. Robinson, Prac. Init. C. ., vol. xv. p. 196. 1 Geol. Mag., 1869, p. 385 ; and 'The Ancient Fauna of Essex,' Trout. Eistx FitU Club, vol. iii. p. 1. See also Holmes, Enex Nat., vol. xii. p. I. M. Christy, Enex Nat., vol. iii. p. I ; J. French, ibid. p. 1 1 ; A. S. Kennard and B. B. Wood- ward, ibid. vol. x. p. 87. For other fossils from alluvial deposits, see Whitaker, Geologj of Undo*, vol. i. p. 476. by Mr. E. T. Newton. 19
 * The section was examined by Mr. T. V. Holmes and the writer, and the bone* were identified