1902] VEGETATION AT WOODS HOLE 439 
offine earth and sand encircles the pool, pushing slowly inward. 
If the contour of the surrounding land is such that the rain 
vulets cut out a gully, the zone of silt deposit opposite its 
mouth indents the pond as a sandy or gravelly delta. These 
borders and deltas of silt become the seat of well-marked plant 
ieties. Gratiola aurea in particular occurs with regularity, 
lits yellow blossoms may indicate to the eye at a distance 
mits of such deposits. If the pond is situated in the deep 
ods, results are produced which are apparently paradoxical, 
will be discussed below. : 
NOTES UPON SUCCESSIVE STAGES. 
ge holes present, of course, the earliest phases, and in the 
‘ones the more advanced conditions are found. Asa type : 
former we may chose Long pond, near Falmouth village. 2 
s about 21% kilometers long, and reaches a depth of 28 
The shores are of the usual morainal materials, and i in 
places precipitous. As usual in such cases, i without 
>, yet its depth and area are such that its” vater is 
ee from aged 
The scanty vegetation admits of being — 
exactness. In the body ofthe pond n no plants 2 
shore appear some filamentous: igac, ane * 
zh e ieccnparent wat: = 
suit was useful. e 
