VEGETATION AT WOODS HOLE 449 
dd to the decaying mass, and produces a zone nearly destitute _ 
f growing plants, widest where the washings of the forest floor 
ily formed may not poe at the margin, for the island of 
egelation is a floating one, and the real bottom of the pool is more 
‘less basin shaped. The islands are in fact floating mats, and 
likely to afford only a very doubtful footing, but by felling” 
ee upon one somewhat smaller than the one shown, it was 
sible to reach the center and learn that in that case there are ey 
3 meters of water in the center on which the floating islan d- 
ts. The detritus resulting from decomposition ae 
