1909] 
Bartlett, Submarine Bog at Woods Hole 
288 
indicates that a zone is more or less regularly inundated by sea water 
at high tide. 
Appropriate values for sea water are not filled in, how- 
ever, because the fresh water table underlies the whole marsh, and 
would, in fact, coincide with its surface if it were not for downward 
displacement by sea water left on the marsh after high tide. 
Even at 
the line of stumps along the water's edge, peat from below low tide 
level is appreciably less salty to the taste than that from higher up. 
It may be that the salt concentration in the water from which deep 
rooting species draw their supply is much less than in sea water. 
Zone 
gal al o) Poe fia 
Cl. concentration 
Sea- 
ward |Center ren 
limit 
* ж ж 
ж ж n 
| 16 
n n n 
16 363 | 375 
n necu um 
375 217 | 158 
n n n 
158 214 2mm 
n n | n 
217 1000 | 1700 
| 
| 
% sea water 
Sea- 
К: Center rna 
x * * 
x VEND 15 L4 
ПНЕ 051 0.48 
0.48 | 0.82 | 1.12 
1.12} 0.84| 0.82 
ОО OTI 
AOsmotic pressure 
in mm, 
Sea- 
Ж Inland 
pier Center limit 
* * * 
* z 2110 
2110 102 95 
95 180 220 
220 | 180 | 180 
180 | 35 21 
| 
In explanation of this table little need be said. 
The first three 
columns give the amount of chlorine found on titration, the second 
three columns the corresponding admixture with sea water, assuming 
the normal chlorine of the ground water to be negligible, and the last 
three columns give the approximate increase in osmotic pressure which 
would correspond to such admixture. 
Perhaps the most remarkable 
fact shown is that in the transition zone, D, the salinity is less than in 
the next zone landward. Of course this would not be true all the year 
round. ‘That such a condition may sometimes obtain is due to the 
fact that zone D marks the line of intersection of the fresh water table 
Along this line there is constant upward 
and the marsh surface. 
seepage of fresh water, which washes away salt spray which is blown 
upon the surface. 
In zone E, on the other hand, the water table is 
below the surface and all salt spray sinks in, to be removed only by 
There is furthermore constant evaporation 
downward displacement. 
of capillary water from the surface in zone E, which results in an 
accumulation of salts at the surface, during dry weather. 
It is obvious 
that from zone D landward the osmotic pressures are too slight to 
influence the distribution of the flora. 
