1909] Bartlett, — Submarine Bog at Woods Hole 998 
Moreover, since the usual kettle-hole pond has no outlet, great sea- 
sonal fluctuation in water level prevents mat-forming plants from get- 
ting a foothold. ‘The pond in a depression of this type remains open, 
and usually has а gravelly beach. 
Mr. Shaw's studies led him to believe that the Woods Hole Chamae- 
cyparis bogs had been formed by the growth of Chamaecyparis on 
floating mats after they had already become firm enough to be occupied 
by а thicket of various shrubs. In accord with this idea, he termed 
the shrubs which are found in the cedar bogs, Leucothoé, Kalmia 
angustifolia, ete., relicts from a former thicket vegetation. In his 
paper three individual bogs are described, designated as "x," “y” 
and “z.” Bog “x” differs from bogs “у” and “z” chiefly in having 
a pool at the center, which Mr. Shaw considers to have been a remnant 
of open water at the center of the pond when Chamaecyparis took 
possession of the mat. Soundings show the incorrectness of this 
seem to have 
“ td 
conclusion. As a matter of fact, bogs “у” and "z' 
developed in depressions of the second type defined in the preceding 
“x” probably in a depression of the third type. 
paragraph, and bog 
In all three bogs, the peat contains Chamaecyparis stumps and roots 
in situ from top to bottom. There 15 no trace of a mat. "Throughout 
their history, the increase in thickness of peat in these bogs has been 
accompanied by a corresponding rise of the water table, the mechanism 
of which is easily explained. 
Let us assume, for the sake of argument, the existence of a flat water 
table beneath an uneven ground surface. Supposing that the capacity 
for loss of water at the ground surface through evaporation and plant 
transpiration were uniform over the whole area, then the amount of 
water lifted by capillarity from the water table to the ground surface 
and there lost by evaporation would vary inversely as the distance 
between the two surfaces. The limiting condition which would be 
approached through the operation of this one factor would be paral- 
lelism of water table and ground surface. Rain, falling upon the 
surface, would be, over a small area, evenly distributed. Ву far the 
larger part would sink into a porous soil at once. Since its movement 
would then be controlled only by gravitation, it would be added to the 
water table in a layer of uniform thickness, and would not tend to 
modify the parallelism of the water table and the ground surface. 
Two factors would tend to have a flattening effect on the water table, — 
the filling of its depressions by run-off water and the operation of 
