9° 
F. W. Oliver. 
cases it seems probable that this form of erosion may play an 
important part in regulating the landward creep of a bank. If the 
view he accepted that the Fleet has been carved out behind the 
Chesil Bank by the deflection of a number of small rivers (pp. 83-4) 
it can hardly be denied that the same forces which have assisted 
in the wasting of the shore line would also have become operative 
in retarding any local tendency that might he shown by the bank 
itself to advance, and by so doing restrict the channel of the Fleet. 
In this way we get perhaps a glimpse of one of the factors which, 
operating automatically, wherever it is required, has been able to 
maintain unimpaired the outstanding peculiarity of the Chesil 
Bank, viz., the marvellous alignment of all the parts throughout 
its length. 
The Relation of the Main Spit to the Hooks. 
An obvious consequence of the shoreward movement of a bank 
provided with lateral hooks is the overwhelming or enclosure of the 
proximal parts of the hooks as the encroaching edge of the mobile 
main bank advances. That this result does in fact occur is manifest 
to any passer-by who cares to examine the series of hooks at the 
“ Marams ” on the Blakeney Bank. The phenomenon of “ hook- 
slide,” however, claims the attention of the botanist on account of 
the reactions which the vegetation exhibits in relation to it. 
It will be readily appreciated that so long as a hook (such as 3 
in Text-fig. 8) remains terminal in position and is directly exposed 
to the surf, so long will it, like the rest of the main bank, be kept 
in a continuous or intermittent state of mobility. When, however, 
by the further growth in length of the main bank the position of 
the hook ceases to be terminal (as in 2 or 1, Text-fig. 8) and its 
flanks are washed only by the protected and relatively quiet waters 
of the estuary, the hook enters on a long phase of dormancy. 
This phase of rest, wherever it has been studied (Blakeney, 
Hurst Castle, Hamstead Dover), finds expression in an altered 
vegetation or “ succession ” which contrasts strikingly with the 
pioneer vegetation of the main bank. New plants not found on 
the main bank make their appearance, whilst others characteristic 
of the main bank no longer occur. There is, however, a residuum 
of plants common to the two types of habitat. 
The main bank slowly driven shorewards encroaches not only 
on the marshes but also on the hooks, embedding them as the main 
trunk of a thickening dicotyledonous tree embeds its branches 
