from its interior. Many large estuaries are now completely 
filled up, which are known to have formerly existed ;* whilst, 
from the remains of forests below the ordinary level of the 
sea, it is clear that the coastal boundary once extended 
far beyond its existing limits. To account for this last- 
named fact it has been supposed that a higher ridge of land 
may have once existed beyond the present tidal line, serving 
to protect a plain lying below the sea level, of which the 
islets still occasionally visible are a portion, and that this 
ridge was either gradually worn away by the continual action 
of the oceanic currents, which are remarkably strong off 
the Lincolnshire coast, or suddenly broken down by some 
extraordinary combination of wind and tide, upon which the 
low tract behind it would also of necessity become the prey 
of the ocean. It has also been suggested that as sandbanks 
DO 
off this shallow coast have been repeatedly known to dis- 
appear, and to form again on other spots with great rapidity 
in long lines parallel with the shore, a continuous barrier 
may have been thrown up under some extraordinary 
combination of wind and tide, behind whose sheltering 
limits vegetation might soon demonstrate its power, so as to 
gradually produce a forest that existed for some centuries, 
until at length that element from which it had been rescued, 
putting forth its whole strength, broke through the boundary 
of its own creation, and again claimed its supremacy over 
the tract beyond it. This theory is supposed to have 
been strengthened by the fact of the destruction in the 11th 
century, of a great part of Earl Godwin's lands on the 
Kentish coast, whose site is still so often and so fatally 
indicated by the Goodwin sands of Deal, and whose surface 
is exposed to view during low tides ; but I believe both 
* Such as Bicker Haven, seven miles long, which still remained a salt marsh 
in 1611, being marked as such, at that date, by Hondius, on a map of the lowlands 
of Lincolnshire, &c, he published at Amsterdam, and which must have entirely 
altered the outline of the Wash. 
