GEOLOGY TABLE OF STRATA FOUND IN SUSSEX Period Character of the Strata Approximate thickness in feet Recent Peat . . . . Alluvium Blown Sand Shingle Beaches Very local . Usually muddy. Clean sand . . Flint pebbles I to 5 up to 60 up to 20 up to 20 Pleistocene and Palaeolithic Brickearth . Coombe Rock and Valley Gravel Raised Beach . Glacial Deposit. Plateau Gravel . Clay with Flints Sandy loam Ans^ular detritus, mainly flint and c"halk Shingle, sand and clay .... Large erratics Angular gravel Angular flints and clay, on chalk . thin thin Bracklesham Beds Bagshot Sands . London Clay . Woolwich and Reading Beds Shelly sand, clay and thin rock . . 500 or 600 Greenish sands thin Clay, thin sands and Bognor Rock 300 Red-mottled clay, coarse sands, pebble beds, lignite and blue clay 80 to 130 Upper Cretaceous Upper Chalk and Chalk Rock Middle Chalk and Mel- bourn Rock Lower Chalk . Upper Greensand Gault . . . Lower Cretaceous Folkestone Beds Sandgate Beds . Hythe Beds . . Atherfield Clay Weald Clay . Upper Tunbridge Wells Sand Soft chalk, with flints Harder chalk, with few or no flints Grey chalk, marly below. Greenish sand, sandstone and malm rock Blue marl, coarse sand at the base . ^oarse sane Grinstead Clay . . . . Lower Tunbridge Wells Sand Wadhurst Clay Ashdown Sand Fairlight Clay Fine sand and clay Sand, sandstone and chert, calcare- ous above Shelly clay Blue and red-mottled clays, with thin sands, Sussex marble and Horsham stone ^Sand and sandstone, with layers of Tilgate stone at the top . Cuckfield Clay ,Sand and sandstone Clay and sandstone Sand and sandstone Shaly clay . . Fine sand Clay and thin sands 500 to 700 200 160 to 200 40 to 80 300 o to 140 30 to 100 25 to 200 thin 600 115 15 70 100 100 130 150 360 Purbeck Beds . Portland Beds . Kimeridge Clay Corallian Oolite Oxford Clay . Shales and limestones with gypsum . Soft sandstones and shales Black shale with ammonites, etc Sands and thin oolitic limestones Dark shale and thin limestone . 400 105 1,290 222 over 1 20
