GEOLOGY OF FOLKESTONE — THE GAULT. 
203 
onward progress of the waters ; the flood-tide striking against which 
would bend over to one side, as indicated by the direction-arrows in 
the h'gnogi'aph, until the time of ebb, when it would flow out with a 
strong current, carrying with it the debris, and thus the cause of the 
Lign. 19. — Theoretical Map of the Action of the Channel Tides in the Denudation of the 
Wealden Area. 
The outlines of England and France have been adopted as they are now delineated on 
ordinary maps, and no attempt at restoration has been made. At the "peninsula" period 
referred to the channel must have been naiTower ; but the outlines of the coast would pro- 
bably have so nearly approximated to the present coast-lines as to render them sufficiently 
accurate for the elucidation of our theoretical speculation. The dotted curves indicate the 
hourly progress of the tidal wave ; the interrupted lines with occasional arrows show the 
chief direction and force of the tidal stream in flowLag and ebbing, by which the denudation 
of the Weald is presumed to have been effected. The existing coast-line of the Wealden area, 
the Boulogne coast, and the cliffs of Dover and Calais are indicated by faint shaded outlines, 
as are also the river-valleys, or cross-fractures of the Weald district, the central ridge of 
which, or axis of elevation, is shown by the line composed of alternate bars and dots. 
clean surface of the Weald and the general absence in the few superficial 
deposits of any organic remains, the denudation being a tidal one. 
The cross-fracture valleys on the south side of the Wealden anti- 
clinal, or central ridge of elevation, would have afforded numerous 
openings on the English side of the channel-crack, up which the pent 
tide would have poured, and hence the reason why the greater denu- 
