Forest Development in the Adirondacks 35 
soil is well drained. The water table lies very near the 
surface —in July, 1920, it was only six inches below the 
surface — except in very dry seasons when it sinks 18 inches 
or more. ‘The soil is a very rich black alluvium almost muck 
like in places, covering the underlying sand to a depth of some 
two feet. Much of it is the product of the vegetation itselt, 
but in flood periods, as for example in the spring of 1920, the 
river cuts away its low bank and the black soil is deposited 
as mud over the flat meadow. It is well mixed with mineral 
constituents. Angle worms are found under the close meadow 
sod as in rich cultivated fields. These qualities stand out in 
sharp contrast with the soils of the sand plain generally and one 
is Impressed at once by the absence of sphagnum, heath shrubs 
and all the constituents of the bog series. Perhaps no more 
striking example could be cited of the role of edaphic factors 
in determining the vegetation cover and its course of develop- 
ment (sequence of associations). There are two prominent 
associations — (1) the marsh meadow, (2) the alder thicket. 
See fig. 25. 
(1) The Marsh Meadow 
Within the area covered by Grasse River sand plain, the 
marsh meadow occupies the greater part of the flood plain. 
It forms a series of pastures in the bends of the widely mean- 
dering stream. Its extent and persistence (freedom from 
shrub invasion) are promoted by the practice annually of 
mowing the hay for stock feed. In general the beaver meadow 
grass, Calamagrostis canadensis is the dominant species in the 
association, but where the meadow has been pastured and 
longer mowed, other grasses have become even more prominent. 
Thus there are almost pure stands of northern manna grass 
(Panicularia laxa), of fowl meadow grass (Poa triflora), and 
silk grass (Agrostis hyemalis), while the constantly wet ground 
is covered by tussock sedge (Carex stricta). Other grasslike 
marsh plants occur in considerable frequence, e. g., Scirpus 
cyperinus, Carex intumescens, and there is the usual scattering 
occurrence of such marsh herbs as [ris versicolor, Thalictrum 
