400 Salisbury .— The Soils of Blake ney Point : A Study of Soil 
tinuous carpet, and the organic range is between 0-30 per cent, and 0-96 per 
cent. The average for seventeen localities is 0-525 per cent., or approxi- 
mately 7-2 grm. per cubic decimetre. The highest values are associated with 
a continuous covering of Cladonia (C 41, C 42) or moss (D 36 a-c, D 39, Di), 
If the two estimations for ridge C may be taken as typical, then the organic 
content here rises to nearly 12 grm. per cubic decimetre. 
Long Hills. The lowest value on these still older dunes correspond 
with the average for ridge D, whilst the average for the. Long Hills is 
almost exactly double, viz. 1*154 per cent, or about 15*5 grm. per cubic deci- 
metre. The observed range was from 0*56 per cent, to 2*69 per cent., the 
highest value being associated with the occurrence of Polypodiinn vidgare. 
The Hood. As already indicated, this is subject to some accretion, and 
there are, moreover, numerous rabbits which continually disturb the normal 
edaphic relations by bringing to the surface the less organic sand from 
below. This factor operates throughout the dune area, but especially on the 
Long Hills and Hood. Despite these disturbing influences, the surface soil 
of the Hood shows a much higher organic content, ranging from o*6i per 
cent, to as much as 6*34 per cent., with an average of 2*69 per cent., or 
nearly 34-5 grm. per cubic decimetre. 
A thirty-year-old pine wood on Holkham dunes showed an average 
organic content of 13*2 per cent., or over 150 grm. per cubic decimetre, in 
the first four inches of soil. 
The dunes of successively greater age thus exhibit a perfect gradation 
in organic content, so that when more dune systems have been examined in 
detail, it may be possible to determine their approximate age by this means. 
If we represent the organic content of the youngest dunes by unity, 
the proportional values are approximately as follows : embryo dunes r ; 
main ridge, 1*3; Laboratory ridge, 1*4; ridge C, ? 2*3 ; Long Hills, 3*0; 
Hood, 6-7. 
Table V. Summary of Data respecting Organic Content of Dunes. 
Region cf. map) J and G E D C BA (oldest phase) 
Av. % 0-360 0-501 0-52-5 o-86? 1-154 2-69 
Weight per cubic decimetre 5-148 7-164 7-245 n-868? 15-509 34*459 
The appended data (Table VI), obtained from a transect of three samples 
from the Southport dune system, indicate that the same type of sequence in 
edaphic phenomena probably characterizes dune systems in general. 
Table VI. Transect Southport Dunes ( Samples 0-6 in). 
Water 
capacity. 
Dune near sea face 23-5 
Medium aged turf-covered dune 30.3 
Old dune near fringe of cultivation 44.0 
p. H. 
Total 
carbonates. 
0/ 
Organic 
content. 
°/ 
Silt + clay. 
°/ 
7*4 
Vo 
3 * 5 - 4* 8 5 
Vo 
0-30 
Vo 
o -34 
/• 1 
2.1--3.60 
2-92 
1.07 
6-8 
0-5-1 -6 
3-25 
I-IO 
