CHAPTER XX. 
Eocene formations, continued — Basin of the Cotentin, or Valognes — Rennes — ■ 
Basin of Belgium, or the Netherlands — Aix in Provence — Fossil insects- 
Tertiary strata of England — Basins of London and Hampshire — Different 
groups — Plastic clay and sand — London clay — Bagshot sand — Fresh-water 
strata of the Isle of Wight — Palaeotherium and other fossil mammalia of Bin- 
stead — English Eocene strata conformable to chalk — Outliers on the elevated 
parts of the chalk — Inferences drawn from their occurrence — Sketch of a 
theory of the origin of the English tertiary strata. 
Having in the last three chapters treated of the Eocene 
formations of different parts of France, we now propose to 
examine those which are found in the south-eastern division of 
England; but before we pass from the continent to our own 
island, we may briefly advert to several other spots where 
Eocene deposits have been observed. Their geographical posi- 
tion will be found delineated on the annexed map *. 
MAP OF THE PRINCIPAL TERTIARY BASINS OF THE EOCENE 
PERIOD. 
No. 62. 
HIS Primary rocks and HHH [Eocene formations, 
strata older than the carboniferous series. 
N.B. The space left blank is occupied by secondary formations, from the old red 
sandstone to the chalk inclusive. 
* This map is copied from one given by M. Desnoyers, Mem. de la Soc. d'Hist. 
Nat. de Paris, 1825, pi. 9 ; compiled partly from that author's observations, and. 
partly from Mr. Webster's map, Geoh Trans.j 1st series ; vol, ii. plate 10. 
T 3 
