SYNOPTICAL TABLE OF BRITISH AQUEOUS ROCK-GROUPS, ARRANGED IN THEIR ORDE 
Each Group represents a Geological Perio 
Taking the smallness of its area into consideration, no country equals England in the extent of illustrating the geologica. 
on the Continent. In North America the Secondary 
CLASSES. 
SYSTEMS.* 
POST -PLEISTOCENE 
(Or Post-Pliocene) — Lyell. 
FOEMATIONS.— Maein-e Ttpks. 
Deposits now forming around the shores of the British Islands. 
Blackpool (Lancashire) Shell-sands. 
Devonshire Kaised Beaches. 
Belfast low-level (British) Shell-clays 
? Portrush SheU-gravel. 
PLEIST0CENE-i7/e« 
(Glacial — Forbes) . 
Kelsey (near Hull) Marine Shell-sands, with Corlicula Jluminalii. 
(near Dublin) Cj/therea Chione, Gravel. 
Howth 
English Midland sub-Arctic Shell-gravels. Wicklow and Antrim SheU-clays. 
? Selsea (Sussex Levels) "Yellow Drift-clay" (Godwin- Austen). 
Lanarkshire (Arctic) SheU-clays. 
o 
I 
PLIOCENE— iye?/. 
Contains vwre (a large num- 
ber) existing sp. of shells 
than occur in the two next 
antecedent Systems. 
MIOCENE— Xj^e^Z. 
Contams a less number of 
existing sp. than the Plio- 
cene. 
EOCENE— Lj/eW. 
The earliest System contain- 
ing living (few) species of 
shells, — the daw7i of ex- 
isting testaceous life. 
Norwich Crag. 
Waitoii Naze (Essex) Eed'Cr'ag! 
Suffolk Crag. 
Bridlington and ChiUesford SheU-clay, 
Wexford Shell-gravei. 
(Not known in British Isles : possibly swept off by denudation. Occurs 
in France, Germany, Belgium, etc.) 
Barton Clay. 
Bracklesham Clay. 
London Clay and Thanet Sands. 
00 
II 
CRETACEOUS. 
Characterized by Chalk 
{creta) rocks. 
(Not known in British Isles.) Macstricht and Belgium. Tuff-chalk, etc 
South of England Chalk. Antrim " White Limestone." 
Gaiilt, and Wiltshire (" Upper'') Greensand. Antrim " Mulatto Stone." 
SEC 
-Meso: 
NEOCOMIAN. 
Type deposits occur at 
Neufchatel (Neocomum) 
in Switzerland. 
Atherfield (Isle of Wight) clay. 
(The lowest marine portion of this System appears not to be developed 
in British Isles.) 
* The student is strongly recommended to commit the column of" Systems" to memory. 
