OF WESTERN EUROPE AND THE MEDITERRANEAN COASTS. 
on 
and Mammalian remains together with palseolithic flint implements, while the bed 
marked h in my original section,* and which, after descending the hill slope, passes 
beneath the alluvium in the valley, represents the rabble-drift such as is met with 
on slopes. 
Since that section was taken another (flg. 4) very illustrative section, corresponding 
in its main features with the head on the Channel coast, was for a short time to be 
seen in a road-cutting in the suburb of Mercade, north of Abbeville. This section 
showed the same remarkable reversal of the out-cropping edges of the beds, so 
conspicuous at Brighton and Portland, with additional features of some Importance. 
Fig. 4.— Section of Buhhle-Drift on the slope of the hill to the north of Ahheville. 
f 1. Coarse angular flint- and clialk-rabble. 
I 2. Chalk-rubble with seams of Loess and flint gravel. Land shells (^Ilelix —several species, Fupci 
marginata, &c.) abounded in this bed.f 
3. Coarse brown loam or brick-earth, with dispersed flint gravel and a seam of it at base. 
4. Mixed rubble derived from the underlying beds. 
The dip of the base line should cori’espond more closely with that of the surface. 
I saw no Mammalian remains nor any shells other than land shells. The slope 
above is bare with the exception that about half-way up there is a cavity, a', 10 to 
15 feet deep and filled wdth chalk debris and brick-earth. The summit of the hill is 
capped by plateau Loess. The total thickness of the beds Nos. 1 to 4 (fig. 4) may 
be estimated at about 40 feet. This rubble possibly forms, at Porte Mercade, the 
bed of ochreous flint gravel in which M. Boucher de Perthes found a considerable 
number of paleolithic flint implements. 
Besides the unusual abundance of land shells, this section is of interest from the 
circumstance that whereas at Brighton and Sangatte the rubble is piled up without 
distinct divisional lines, here, on the contrary, there are well-marked main divisions. 
To whatsoever cause this may be due—whether to the lesser force of the effluent 
currents than on the coast wLere the successive layers are more intermingled and the 
divisional lines rendered more obscure, or to the position being more sheltered, I cannot 
say. In any case, "we have here three major divisions corresponding with three main 
* ‘ Phil. Trans.’ for 1860, figs. 1, 2, p. 284, and Plate 10, section 1, 
t On my first visit I bad not time to make a complete collection of these shells, and when I retuimed 
the section was covered over. 
