VALLEY DRIFT, 6 feet;-- Sand 3 0 Gravel 3 0 LONDON CLAY, 86 feet;-- Blue Clay 7 0 Hard Brown Clay, with claystones 68 0 Brown Sandy Clay 2 0 Hard Brown Sandy Clay, rotten at bottom 9 0 WOOLWICH AND READING BEDS 63 0 THANET SAND, 40 feet;-- Green Sand 2 0 Brownish-green Quicksand and Pebbles 2 0 Brown Sand 2 0 Grey and Brownish-green Sand 2 0 Green Sand and Pebbles 2 0 Brown Sand 2 0 Green Sand and Pebbles 15 0 Grey Sand and small Pebbles 2 0 Dark Grey and Green Sand 10 6 Green Sand and Green-coated Flints 0 6 ------- To Chalk 202 0 Chalk Flints 0 6 Hard Chalk and Water 2 0 ------- Total 204 6 ------- The water-level is some 103 feet from surface, and the yield 60,000 to 70,000 gallons a day. [Illustration: WELL AT CHARRINGTON'S, MILE END. Figs. 251-253.] _Norwich_.--Well at Coleman's works. After a few feet of alluvium the borer passed through hard chalk with flints at distances of about 6 or 7 feet apart, for 700 feet, with the exception of 10 feet at the depth of 500 feet where the rock was soft and of a rusty colour, thence the flints were thicker, namely, about 4 feet apart to the depth of 1050 feet. After this 102 feet were pierced of chalk, free from flints, to the upper greensand, a stratum of about 6 feet, and then gault for 36 feet. The whole boring being full of water to within 16 feet of the surface. Section of strata;-- Feet. Alluvium 12 Hard Chalk, with flints 483 Soft Chalk 10 Hard Chalk 190 Hard Chalk, flints closer 350 Chalk without flints 102 Upper Greensand 6 Gault 36 ---- Total 1189 ---- [Illustration: GEOLOGICAL SECTION FROM NIORT TO VERDUN, THROUGH THE PARIS BASIN. Horizontal scale, 90 miles the inch. Vertical scale, 1500 feet the inch. Fig 254.]