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 GEOLOGY I. BORING AT RICHMOND WATERWORKS, 1 876-84. * Thickness in feet Kind of Material Geological Classification 10 160 22* 300 150 220 16 IO 8 7 i 207^ Made ground and sandy gravel Clay Mottled clays with a bed of sand Light grey and greenish sand with green- coated flints at base White chalk with flints Greyish and cream-coloured chalk without flints Grey marly chalk passing downward into chalk marl Calcareous sandstone Pale and dark blue clay with glauconitic sand and phosphattc nodules at base Limestone, somewhat oolitic, with thin bands of clay Limestones, more or less oolitic, with a thin band of clay and some layers of calcareous sandstone Alternations of red, white and mottled sand- stone with red and variegated marls ; dipping steeply Total depth Recent London Clay "j Reading Beds I Eocene Thanet Sands I Upper Chalk Middle Chalk Lower Chalk Upper Greensand Gault Upper Creta- ceous ( ?) Lower Greensand. (?) Lower Cre- taceous Great Oolite Series. Jurassic (?) New Red Sandstone. (?) Triassic II. BORING AT STREATHAM COMMON FOR THE SOUTHWARK AND VAUXHALL WATER COMPANY, 1 882-88.* Thickness in feet 10 153 43i 35 22l 2I 9 188^ 38* 138 1,258 Kind of Material Gravel and mud Blue clay, sandy and pebbly at base Black and mottled clay, sandy clay and thin beds of green sand Green and grey sand, with flints at base White chalk with flints Hard greyish chalk without flints Grey chalk passing downwards into chalk marl Greenish-grey calcareous sandstone Firm clay with phosphatic nodules at base Alternations of oolitic limestone, calcareous sandstone, sandy clay and clay Greenish-grey, reddish and mottled sandstone, with bands of hard reddish clayey rock ; dipping steeply Total depth Geological Classification Recent London Clay Woolwich and Reading Beds Thanet Sands Upper Chalk Middle Chalk Eocene Lower Chalk Upper ceous Creta- Upper Greensand Gault Great Oolite Series ) ~ ,, ,-, ,,, ,, > Jurassic (( Forest Marble) ) J Triassic (?), or Devonian (?) 1 For fuller details see Prof. J. W. Judd and C. Homersham, Quart. Journ. Geol. Sac., vol. xl. (1884) pp. 724-783 ; and vol. xli. (1885) pp. 523-527. 2 Mem. Geol. Survey, 'The Geology of London,' vol. ii. (1889) pp. 224-229. 19