200 Mr.8. V. Wood on the Red Crag 
the high lands of the north of England would exempt them from 
any part that glaciers may have played in the distribution of the 
great boulders of that part of England. 
Notwithstanding the confusion that has existed as to the rela- 
tionship to the Drift borne by the freshwater formations of Grays, 
Ilford, Clacton, Stutton, Copford, Lexden, Hoxne, &c., I take it to 
be now well understood that these and similar formations in other 
counties are altogether posterior to the Drift period, having been 
deposited in the valleys that resulted from the upheaval of the bed 
of the upper-Drift sea, and from the denudation that accompa- 
nied such upheaval. Being limited for space, I have not referred 
to these beds, but confined myself to marking into the map 
of the Red Crag district the only deposit of this nature (that of 
Stutton and Wrabness) occurring within it. It will be seen that 
the Stutton and Wrabness beds rest on the London Clay, which 
previously to their deposition had been laid bare by the denu- 
dation of both Drifts, and which denudation accompanied those 
symmetrical movements that elevated the upper-Drift sea-bed, and 
gave rise to the inequalities of surface over the East of England 
which form the subject of my paper on the valley-system before 
alluded to. The other correlated freshwater deposits named 
above are identical with that of Stutton in their position rela- 
tively to the Drift, although they vary in the bed they rest upon, 
according as the denudation has in a greater or less degree 
eroded the valley previous to their deposit; but, within the limit 
of the period elapsed since the upheaval of the Drift sea-bed, 
these deposits may to a small extent vary in age among them- 
selves. The greater contiguity of the Thames valley to the 
centres of upheaval producing the valley-system, but more par- 
ticularly its greater contiguity to the great rectilinear upheavals 
of the Weald and South of England which succeeded the gene- 
ral upheaval producing the valley-system, has, as I conceive, 
caused in that valley greater changes of level among its deposits 
than is the case with the beds accumulated in the valleys of the 
rivers of northern Essex. The precise correlation in age of thie 
valley-deposits of the respective areas is therefore, I think, to 
be satisfactorily arrived at rather by close paleeontological analy- 
sis than by comparisons of level and physical structure. 
APPENDIX. 
Sections of Red Crag. 
ALDERTON. On the Ramsholt road, three-quarters of a mile from Alder- 
ton.—Fifth stage, lamimated with red sands, and false-bedded. 
No line of erosion visible. Traces of a beach stage at bottom. 
Nodule-band occurs. ; 
Bawpsey. Sea-cliff.—Fifth stage. Fourth and two other beach stages. 
