the Upper and Lower Drift of the Eastern Counties. 405 
which result from the regular and constant intermixture of the 
fresh water of rivers with the sea-water. This conjecture also 
receives some support from the circumstance that the included 
shells of the Loess appear to become rarer as the distance from 
the Rhine increases, and from the fact that the Hesbayan mud, 
argillaceo-sandy in Belgium, becomes on the extreme east of 
Suffolk more clayey, but yet less so than further to the west, and 
its included chalk débris are there but scanty; while as we go west- 
ward, and approach the region of the oolitic clays, from which so 
much of the argillaceous material of the Boulder-clay of the east 
of England has been derived, the clayey character of the deposit 
becomes more decided. Approaching the Chalk region, as 
well as over it, the extensive intermixture of chalk-detritus 
shows that the adjacent material largely contributed to the 
sediment, and that little or nothing was derived from the Hes- 
bayan area. Over the Eastern Counties also the Boulder-clay 
is destitute, so far as hitherto observed, of fossils; so that it 
would seem to form a sort of neutral ground between the Loess 
with its included land-shells, and the Boulder-clay of the north 
with its deposits of marine shells. 
I have not been able to find any description of the upper 
Crag of Antwerp calculated to throw any light on the relation- 
ship borne by that deposit to the Campinian sands, or showing 
whether the transition that exists in Suffolk between the Red 
Crag and the lower Drift obtains also in Belgium; and, indeed, 
it would seem that the level state of the country around Ant- 
werp forms an obstacle to a satisfactory investigation of that 
question. 
* * X* * * * 
In the paper on the “ Red Crag and Drift” (‘ Annals,’ March, 
p. 185) I observed, in reference to the passage-beds between the 
Red Crag and Drift, that I understood from Mr. Prestwich that 
he no longer adhered to the section of that place published by him 
in the Quart. Journ. Geol. Soc. (vol. v. p. 345). I, however, 
should have said that it was his interpretation of some parts 
of that section, and not the order of superposition, to which 
Mr. Prestwich does not now adhere. It will be seen, by a 
comparison of the two sections, that, in point of superposition, 
there is no material difference between them. It was in respect 
of the unconformability of these beds to the Red Crag that 
my views differed from those expressed by Mr. Prestwich in 
1849. 
