9 § 
T. G. Hill. 
was drawn to the extension of the vegetation in various directions, 
especially to the extension of the area of vegetation under the dunes 
(Fig. 3, A and B). 
A detailed map was made of the apex of this advancing vegetation 
in the autumn of 1907, in order that the progress of colonisation 
Fig. 3. Sketch map of the Bouche d’ Erquy shewing the complex system 
of natural irrigation-channels by which the tide gains access to the marsh. 
The plant-associations are not represented. The areas adjacent to the two 
principal channels (heavy black) consist of established turf, whilst the region 
on the right, running up to the dunes, corresponds to an earlier phase of 
development. The shading at A—A and A' marks the pioneer zones of 
Salicornia vadicans, whilst at B—B (cross-hatching) Salicornia ramosissima plays 
an analogous role. The banks of the main channel are not drawn in its lower 
part, but its course is indicated by arrows. Scale 1/8750. 
could be kept under close observation. A careful comparison was 
made this last autumn, when it was found that a marked advance 
had taken place. On the north-western face, the vegetation had 
advanced about forty feet on previously uncolonised sand, the 
