394. Mr. S. V. Wood on the Belgian Equivalents of 
Norfolk *, I showed that this lower Drift was but the deposit of a 
bay which, subsequent to the accumulation of the Red-Crag beds, 
advanced inland more by erosion than by depression. I also 
attempted to show that by the time this bay had thus reached, 
on the west, the western side of Suffolk, and on the south-west, 
the centre of Essex, a general submergence of the country 
terminated this accumulation of sands and gravels, and caused 
the precipitation, alike over those beds and over the older forma- 
tions forming the terrestrial surface of the period, of the mud 
or clay that now occurs more or less continuously over so large 
a portion of the British islands, and is commonly known as the 
Boulder-clay. I also adverted to the probable great extension of 
this lower-Drift bay in an eastwardly direction over the north of 
Europe, from which direction the abundant pebbles of quartzite 
occurring in the gravels appear to have been derived. 
My object is now to endeavour to show that in the Loess of 
Belgium and the Rhine we have the extension of the upper drift 
that in the British isles is represented by the Boulder-clay, and 
that in the Campinian sands, spread over all the north of Bel- 
gium, and enveloping beds of rolled stones, described by more 
than one continental geologist, we have the precise equivalent 
of the English sands and gravels described by me under the 
term “ lower Drift.” 
The relationship of the Loess to the Boulder-clay seems to have 
attracted the attention of Sir Charles Lyell ; for, in his memoir on 
the Belgian Tertiaries+, he observes: —“In regard to the relative 
ages of the loess and the northern drift with its erratics, the 
only positive information which I obtained during this tour was — 
on crossing the Meuse from Maestricht to the right bank of that 
river, opposite the city. Here, in company with M.van Rymsdyck, 
I observed that the sands of the Limburg tertiary series were co- 
vered by a bed of quartzose gravel with erratics, and this again by © 
loess 30 feet thick. The locality alluded to is the tableland of 
Rassburg, near Geulem, which is about 300 feet above the Meuse, 
and about 450 feet above the level of the sea. The erratics are — 
some of them very angular and more than 2 feet in diameter, con- 
sisting of quartzose slate, similar to that of the Ardennes, from 
which they are believed to have been transported. Such an in- 
stance of the superposition of loess to a certain class of erraties 
will not justify the conclusion that the origin of the loess gene- 
rally was of later date than the northern drift. I should rather — 
infer from the fact here mentioned, that the transportation by — 
ice of large blocks was still going on when a part of the Belgian — 
loess was deposited ; in other words, the glacial epoch coincided, — 
* Ann. and Mag. of Nat. Hist. ser. 3. vol. xiii. p. 185. 
+ Quart. Journ. Geol. Soc. vol. viii. p. 281. 
os 
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