402 Mr. S. 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 

 {i. e. the Loess, or limon Hesbayen) occurs in the north-east 

 provinces of France, south of the Ardennes j 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 in the 

 cretaceous and tertiary strata, and those that are newer than 

 those valleys, as is evident from his identification of the 

 Maestri cht 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. Elie 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. 



