316 
EOCENE PERIOD. 
[Ch.XXII. 
extremity of the Isle of Wight, part of the fresh-water series 
is vertical, like the marine. Hence it is now ascertained that 
as the chalk is horizontal at the southern extremity of the Isle 
of Wight, while it is vertical in the centre of that island, so the 
Eocene strata are horizontal in the north of the island, and 
vertical in the centre. We have only to imagine that the great 
flexure of the secondary and tertiary beds, so ingeniously 
suggested by Mr. Webster in his theoretical section % extended 
to the fresh-water formations, in order to comprehend how a 
very simple series of movements may have brought the whole 
of the Isle of Wight groups into their present position. 
We are unable to assign a precise date to the convulsions 
which produced this great curve in the stratified rocks of the 
Isle of Wight ; but we may observe that, although subsequent 
to the deposition of the fresh- water beds, it does not follow that 
it was not produced in the Eocene period. It may have been 
contemporaneous with those movements which raised the cen- 
tral parts of the London and Hampshire basins, which, as we 
before explained, were subsequent to the principal elevation and 
denudation of the central axis of the Weald. 
Land has certainly been elevated on our eastern coast since 
the commencement of the older Pliocene period, as is attested 
by the moderate height attained by the crag strata-}-. But these 
changes of level may have been partial, and if the crag does not 
extend farther over the Eocene formations, and into the Weald 
Valley, it is probably because those regions were dry land 
when the strata of crag were forming in the sea. 
The first land that rose in the south-eastern extremity of 
England may have been placed, as we before hinted, where we 
now find the central axis of elevation in the Weald. Perhaps 
the chalk islands there formed may have supported that 
tropical vegetation whereof we find memorials in the fossil 
* Englefield's Isle of Wight, plate XLVII. fig. 1. 
f We alluded, at p. 182, to the supposed discovery of recent marine shells at 
the height of 140 feet above the sea in Sheppey ; but we have since learnt from 
Professor Sedgwick, that the information communicated to the Geological Society 
on this subject was erroneous. 
