44 The New-York State College of Forestry 
worthy features of the plains of the Oswegatchie and has been 
noted also in other similar dry heaths of the Cranberry Lake 
region. 
SUMMARY 
1. The Grasse River Marsh area physiographically con- 
sidered is one of a series of sand plains occurring in or on the 
borders of the Adirondacks, formed under certain drainage 
conditions (presumably glacial) which have ceased to be 
operative. 
2. By reason of its low lying position and of the presence 
of eskerlike sand ridges which intercept its drainage, the larger 
part of the area here considered is covered by peat which at 
present is occupied by a vegetation complex in which sphagnum 
is the controlling element resulting in typical bog conditions. 
3. The bog vegetation presents a series of plant associations 
which appear clearly to stand in a developmental relation begin- 
ning with open sphagnum-sedge meadow and culminating at 
the present time in the initial stages of a balsam swamp forest. 
4. This study supported by evidence from other situations 
in the Cranberry Lake region appears to warrant the conclusion 
that while black spruce-tamarack-arborvitae bog forest is a 
persistent association and may remain in effect an edaphic 
climax association, it nevertheless tends to create soil conditions 
which introduce balsam and its swamp forest associates and 
may in fact go over definitely into balsam swamp forest. The 
more thorough decomposition of peat into a blacker more muck- 
like condition indicates better aeration at this stage of transi- 
tion to balsam swamp. What relation such a bog originating 
balsam swamp forest may bear to balsam flat and to the Adiron- 
dack Climax forest has not been determined. 
5. A second feature of the Grasse River Marsh area consists 
of flat and very slightly elevated or low undulating sands 
which while they must be classified as wet lands are still well 
drained enough or lie high enough above the summer water 
table so that sphagnum is excluded. Hence, true marsh or 
semi-marsh as contrasted with bog conditions prevail as shown 
in the present secondary associations of grasses, sedges and 
