4 i 8 Salisbury . — The Soils of Blakeney Point : A Study of Soil 
assumes a very dwarf habit in comparison with that of plants growing 
on the crest, whilst Plantago Coronopus , which is found in the normal state 
on the crest, here assumes the forma pygmaea (that this is only a habitat 
form and not a variety has been experimentally demonstrated by the 
writer). 
The Main Beach. 
The data regarding the main beach (Appendix, Table XIII) serve 
to show its close resemblance as a whole to the younger phases of the 
laterals. There is, however, a marked difference between the bare shingle 
and that covered with vegetation. Whereas the average carbonate content 
of the former is 0-53, that of the latter is 1-39 per cent., whilst the average 
organic content under vegetation is 2-53 per cent, as compared with 0-99 as 
the average for bare shingle. Since drift i$ often carried high up on to the 
main beach, this naturally tends to collect around the Suaeda bushes and on 
the mats of vegetation, so that the organic material supplied by the plants 
themselves is augmented by supplies of drift, which also brings with it 
carbonates in the form of shellTragments. Thus the influence of the plants 
themselves on the stability and character of the shingle soil tends to 
be cumulative in its action. 
Chloride Determinations. 
A few determinations of chlorides for various parts of the area given 
in Table XVI (Appendix), though insufficient to warrant any detailed con- 
sideration, are sufficient to show that the percentage of chlorides is low both 
for the dunes and the crests of the older shingle banks. The main shingle 
bank exhibits considerable variation, and indeed these data seem to indi- 
cate that the percentage of chlorides, except perhaps in the salt marsh 
itself, is chiefly significant in relation to the vegetation, as an index of the 
incidence of tidal inundation. 
The Marsh Vegetation. 
Consideration of the data in Table XV (Appendix) would seem to 
indicate that the differences in p. H. value have little, if any, significance 
in relation to the zones of marsh vegetation. 
These latter are three in number : the Suaeda fruticosa zone, occupy- 
ing the upper edge flanking the shingle ; the Salicornietum , occupying the 
floor of the marsh ; and the Obione zone, situated on the slight slope between. 
Both the averages for all the data and for the transects alone show the 
same relation to hold with respect to the carbonates and organic matter 
present; namely maximum values for the Salicornietum (organic 9*19 per 
cent., carb. 2*55 per cent.) and minimum values for the Suaeda fruticosa 
zone (organic 1-36 per cent., carb. 0-676 per cent.), those for the Obione zone 
