HOW WERE THE EOCENES OF ENGLAND DEPOSITED? 283 
wanting in England, and a gap of incalculable age, only slightly 
lessened by these on the Continent, exists between our lowest 
Eocene and the Chalk upon which it rests. 
Thanet Sands. — These, the lowest Eocene deposits present in 
England, rest unconformably upon the Chalk. They are confined 
in England almost to the eastern area of the London Basin, but 
spread over Picardy and Flanders as the Sables de Bracheux , 
and in Belgium are known as the Landenien inferieur. They 
indicate a very temperate climate. 
Woolwich and Reading Beds. — In the Hampshire Basin these 
are entirely unfossiliferous mottled clays derived from granite, and 
of fluviatile origin. Eastward, near London, lignites and sands 
with brackish-water shells come in. Further east the fluviatile 
mottled clay disappears, and the horizon is occupied by marine 
sand with estuarine shells. A flora was found near Beading, 
valueless for climatal inferences ; but from the presence of palm 
wood, sharks’ teeth and turtles elsewhere, it appears that the 
climate was perhaps even sub-tropical, but still far less hot than 
it became in the time of the London Clay. 
Oldhaven Beds. — These consist of great beds of rolled shingle 
and fine sand, containing sometimes estuarine and sometimes 
marine shells; they are confined to the eastern area of the 
London Basin. 
London Clay. — This is a compact mass of clay of great thick-* 
ness, and spread over both the English 66 basins ” and Belgium. 
It is divided into zones deposited in shallow water, which occur 
at the base ; and deposits from deeper water, but not estimated 
at more than 100 fathoms, which form the upper part of the 
series. Only the beds characterized by shallow water mollusca 
are found in the western area. In addition to the marine fauna, 
a terrestrial fauna and a flora of great extent are known, and it 
is remarkable that these latter present a far more tropical 
assemblage than do the marine products. The beds at Sheppey 
appear to have formed a great river delta. 
The Lower Bagshot Beds. — In the west these are pipe-clays, 
and sands, derived, as were the older mottled clays, from granite,, 
and deposited in fresh-water. Towards and east of London 
they are entirely composed of shingle and sand worn from chalk 
flint and left by the sea. The rich flora contained in this series 
at Studland and Alum Bay forms a similar group to that, the 
fruits of which are found at Sheppey. 
The Bournemouth Series. — From Studland to a mile east of 
Bournemouth, these are purely fresh-water delta deposits. They 
are then overlain by marine or brackish delta mud, by shingle 
and sand, and by a sequence of marine strata at Hengistbury 
Head. This series is particularly interesting, as in it we can 
trace step by step one of the numerous subsidences which took 
