4.02 Mr. 8S. V. Wood on the Belgian Equivalents of 
in the woodcut map *. The great extent of the lower-Drift bay 
in the direction of the north of Germany, and even further still 
to the eastward, becomes, I think, demonstrable; but, as I 
observed in the description of the beds in the Eastern Counties 
(‘ Annals’ for March 1864, p. 199), only a small portion of that 
bay impinged upon England. In the map accompanying that 
description, I did not draw the line indicating the probable 
boundary of the bay in England further north than the western 
side of Norfolk, in consequence of not having been able to make 
the necessary observations along that border to enable me to 
indicate the boundaries in that direction ; I, however, believe 
that the boundary, after crossing the south-east of Lincolnshire, 
skirts the east of that county and runs northwards by Hull 
towards Bridlington ; but for the present I defer any remark as 
to that extremity of the deposit. 
The descriptions of M. d’Archiac, of the extension of the 
ancient diluvium over the north-east of France, do not enable 
one to form an opinion as to how far the conditions that pre- 
vailed during the Drift period on the northern side of the 
Ardennes existed also on the southern. It would seem from 
the descriptions of the French geologists, that the upper Drift 
(2. e. the Loess, or limon Hesbayen) occurs in the north-east 
provinces of France, south of the Ardennes; but to what extent, 
if at all, the lower-Drift beds may be there represented, these 
descriptions do not enable me to form any clear opinion. M. 
d’Archiac draws no distinction, such as I believe does exist, 
between gravels that are older than the valleys formed im the 
cretaceous and tertiary strata, and those that are newer than 
those valleys, as is evident from his identification of the 
Maestricht sand containing rolled quartzites (and which he 
describes as passing under the Loess towards Tongres) with the 
* Sir Charles points out the difficulty of distinguishing between the 
sandy base of the Loess and the Eocene sands upon which it rests, by- 
reason of the occurrence of a large number of derivative fossils in the 
former, washed out of the latter. This fully bears out the statement quoted 
from M. Ehe de Beaumont, as to the source from which the Campinian 
sands have been supplied with their material. SirCharles also instances cases 
in which M. Dumont, from this presence of derivative fossils, regarded 
as of Loess (Campinian) age beds which he (Sir Charles) was inclined to 
refer to the Eocene; and it would seem, from the grouping on M. 
Dumont’s map of the Campinian and Loess beds, that this divergence of view 
is the cause of the discrepancy I have been discussing in the representa- 
tions at Dileghem and Dieghem. As the Campinian beds thin out to- 
wards their margin, near the Ardennes, their distinction from the sub-. 
jacent Eocene becomes probably more obscure than it is further to the 
north, where, from their greater thickness and from the presence of their 
included erratics, a general concurrence of opinion exists as to their exis- 
tence beneath the Loess. 
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