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far as has been dug down ; at the lowest depth, however, trunks or roots are found 
so close together as to justify my former supposition as to the thickness of 
the forest; for whilst clearing out the dyke, the whole road was lined with 
the fragments of the trees thrown up. Oak is the prevailing kind of timber, but 
there are also other sorts whose species I cannot ascertain, though birch and alder 
are, I think, among them. With the trees, at even the lowest depth, are found, 
here and there, very many species of shells, not fossilized, but in a recent state; 
and it is from many of these being land species that we must infer, as I have before 
observed, the inundation of the plain by some river; Helices , and a great variety 
of other land shells, being found among them. If left on the bank as they are 
thrown up, the atmospheric influence soon destroys them ; but I have several pre¬ 
served in my collection which are unlike any I have ever seen, and relative to 
which I should be glad to have the opinion of some more able conchologist. In 
other places nuts and acorns are dug up, from various depths, in a perfect state, 
though apt to crumble to pieces after two or three days exposure to the air. The 
present extremely level state of the surface has evidently been brought about by 
the action of water (probably when receding), filling up or smoothing down the 
inequalities which I have before shewn to have existed. The tide is still kept 
from floating the present surface of the country by embankments on the Trent, 
and even at low water it is still above the level where these sea-shells and nuts 
and acorns are found in deepening the dykes, which might probably be discovered 
even still lower, if the soil were cleared away to a sufficient depth. 
It would appear, then, that the question must be asked, whether the sea has 
risen on the eastern coast, since the washing in of these shells ; and also whether it 
must not have first fallen to allow of the present surface (so much above Refor¬ 
mer deposit left by the sea) becoming high and dry ? It also requires some ex¬ 
planation to account for the great accumulation of soil, to the depth, as I have 
shewn, of at least eight feet, over every part of the plain ; although this is partly 
accounted for by the upper inequalities of surface filling up the hollows, when sub¬ 
jected to the washing of so great a body of water. 
With regard to the former of these two suppositions, the sea has certainly, 
even of late years, made great inroads on this eastern coast, and some suppose that 
this is partially accounted for by its gradual rising above its accustomed level, inde¬ 
pendent of the crumbling nature of some of the cliffs, which leaves them an easy 
prey to the ceaseless dashing of the mighty ocean. With respect to these lands 
having been also formerly covered by the sea, this is abundantly evidenced by 
the numerous species of sea-shells, muscles, and other shells, with wdiich they 
abound. Wliether the anomaly of sea-shells being found by the excavators in 
some parts of the Levels at a similar depth to that at which, in other parts, they 
discover acorns and nuts, may be explained by supposing a slight inaccuracy of 
measurement, and that one or the other may lie in a stratum an inch or two more 
