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cases some miles in width. Hence it will be seen that, though 
the beds were contemporaneous, they were formed at very 
different depths ; and the distribution of the organic remains 
agrees with this supposition. The depth over the shoals 
could not have been considerable, or else the surface w r aves 
would not have produced the effects that I have observed. 
The wealden sandstones, in the neighbourhood of Tun- 
bridge Wells, often shew the action of wave currents in 
a very satisfactory manner. On the whole, the structure 
agrees with the supposition of a rise and fall of the tide 
amongst a number of small low islands, or shoaly sandbanks, 
with narrow channels between them, in fact, very much like 
the mouth of a great river; and the same may be said of 
those in the neighbourhood of Hastings. 
The tertiaries of the Isle of Wight and Hampshire 
present us with a very good example of the accumulation 
of deposits in an estuary. The general conclusions are, 
that the line of this estuary ran from West-by-North to 
East-by- South, which is almost exactly parallel to the axis 
of the Pyrenees, which were formed at the same Geological 
period, viz., after the chalk, and before the lower tertiaries ; 
as though movements parallel to them had bent up the sea 
bed into such an irregularity as to produce an estuary, 
running in the same direction. Some time after this, when 
the lowest part of the tertiaries had been formed, the sea 
bed became elevated so as to produce a coast, part of which 
now remains at the west of the Isle of Wight, which 
produces the differences between the sections at Alum and 
Whitecliff Bays. Afterwards the estuary became more 
and more contracted towards the West, and was at one 
time probably entirely closed, though still open to the 
East. The facts thus deduced from the current structures 
agree extremely well with the distribution of the organic 
remains, which they explain in a very satisfactory manner. 
