SYNOPTICAL TABLE OF BRITISH AQUEOUS ROCK-GROUPS, ARRANGED IN THEIR ORDEII' 



Each Group represents a Geological Periq] 



Taking tte smallness of its area into consideration, no country equals England in the extent of illustrating the geologic? , ^ 



on the Continent. In North America the Secondaiii 



CLASSES. 



SYSTEMS.* 



rOKMATIONS.— Maeine Types. 







Deposits now forming around the shores of the British Islands. 





POST-PLEISTOCEIS^E 

 (Or 3?o.st-I*lioc6ne) — Lyell, 



Bl^-ckpool (Ls-ncs-sliirG) SiiGll-sfliids. JBolfsst 1ow-1g\g1 (Bntisli) SnGll-clfl-ys* 

 Devonshire Kaised Beaches. ? Portrush Shell-graTelJ 







Kelsey (near HuU) Marine Shell-sands, with Corhicula fliminalis . Howth 

 (near Dublin) Cytherea Chione, Gravel. 





PLEISTOCENE-ij/eW 

 (Glacial— Jbrfies) . 



English Midland sub-Arctic Shell-gravels. WicMow and Antrim Shell-clays. 

 ? Selsea (Sussex Levels) "Yellow Drift-clay" (Godwin- Austen). 



TERTIARY. 



— Cainozoic of FldlUps. 





Lanarkshire (Arctic) Shell-clays. 



PLIOCENE— 

 Contains more (a large num- 

 ber) existing sp. of shells 



antecedent Systems. 



Norwich Crag. Bridlington and Chillesford Shell-clay. 

 "Walton Naze (Essex) Eed Crag. Wexford SheU-gravel. 

 Suffolk Crag. 





MIOCENE— ij/ert. 

 Contains a less number of 

 existing sp. than the Plio- 

 cene. 



(Not known in British Isles : possibly swept off by denudation. Occurs 

 in France, Germany, Belgium, etc.) 





EOCENE— L«/e/Z. 

 The earliest System contain- 

 ing living (few) species of 

 shells, — the dawn of ex- 

 isting testaceous life. 



Barton Clay. 



Bracklesham Clay. 



London Clay and Thanet Sands. 



(Not known in British Isles.) Maesti-icht and Belgium. Tuff-chalk, etc' 



South of England Chalk. Antrim " White Limestone." 



GauU, and Wiltshire (" Upper") Greensand. Antrim "Mulatto Stone." 



i 



Atlieriloia (Isle of Wight) clay. 



(The lowest marine portion of this System appears not to be developed 

 in British isles.) 



CRETACEOUS. 

 Characterized by Chalk 

 {creta) rocks. 



NEOCOMIAN. 

 Typo deposits occur at 

 Nourch!it(-l ( ycocomum) 

 in Switzerland. 



* The student is strongly roconuuendod to o<Mnmil the column of" Systems"' lo memory. 



