-----------------+------------------------------------+------------ | | Thickness Groups. | Strata. | in Feet. -----------------+------------------------------------+------------ | | CAINOZOIC, OR TERTIARY. | | | { RECENT | 1 Modern Deposits. | { | | { PLEISTOCENE | 2 Drift and Gravel Beds | 20 to 100 { | | { {| 3 Mammaliferous Crag | 10 to 40 { PLIOCENE {| 4 Red Crag | 30 { {| 5 Suffolk (Coralline) Crag | 30 { | | { MIOCENE {| 6 Faluns (Touraine) Molasse }| { {| Sandstones }| 6000 { | | { EOCENE | | { {| 7 Hempstead Series | 170 { UPPER {| 8 Bembridge Series | 110 { {| 9 Headon Series | 200 { | | { MIDDLE | 10 Barton Beds | 300 { | | { {| 11 Bagshot and Bracklesham Series | 1200 { LOWER {| 12 London Clay and Bognor Beds | 200 to 520 { {| 13 Woolwich Beds & Thanet Sands | 100 | | | | MESOZOIC, OR SECONDARY. | { {| 14 Maestricht Beds | 110 { {| 15 Upper Chalk | 300 { {| 16 Lower Chalk and Chalk Marl | 400 { CRETACEOUS {| 17 Upper Greensand | 130 { {| 18 Gault | 100 { {| 19 Speeton Clay | 130 { {| 20 Lower Greensand | 250 { | | { WEALDEN {| 21 Weald Clay | 150 { {| 22 Hastings Sands | 600 { | | { PURBECK | 23 Purbeck Beds | 150 { | | { UPPER {| 24 Portland Rock and Sand | 150 { OOLITE {| 25 Kimmeridge Clay | 400 { | |