142 College of Forestry 
water as where the Mohawk, the upper Hudson, the Saranac 
and Black river emptied into bodies of water standing at a 
much higher level than at present; second, the beach sand 
laid down during the advances and recessions of the great 
glacial Lake Iroquois, e. g., sand beds of the regions about 
Rochester, the present Oneida Lake basin and westward, the 
basin rim running northward from Oneida Lake to Water- 
town; third, the vast sand beds of the Adirondacks derived 
by weathering of the prevailing granitic rocks and laid down 
upon these, modifying the roughness of rock exposure, form- 
ing deep beds upon slopes and valley sides and having been 
subject to erosion and glacial action— formation of sand 
eskers, etc. The sand deltas of the Saranac at Plattsburg, 
of the upper Hudson below Glens Falls and of the Black 
River below Carthage were evidently formed by sands trans- 
ported from this great Adirondack source of supply. 
A series of typical eases will be instructive as regards the 
course of vegetation, but this important fact is to be borne 
in mind; namely, that in all of these cases, with the possible 
exception of “‘ The Plains,” we are dealing with a secondary 
and not with a primary vegetation condition so far as regards 
the period of human history in New York. Evidence is 
conclusive to the effect that the sand areas above cited were 
originally occupied with heavy forest. The dominant tree 
of the sand delta areas was white pine. Perhaps also on the 
sands of the Iroquois-Ontario basin, where in addition, oak, 
chestnut and tulip-tree formed a prominent element, being 
in fact more abundant than pine at this time. So also, the 
Adirondacks sands were, and of course where not lumbered 
are still forested. In this case, not white pine chiefly but 
mixed forest and often typical climax forest has developed 
upon sand beds. 
(1) A Sand Flat of the Oneida Lake Basin. 
In the particular site chosen for illustration, the sandy sub- 
stratum lies flat, low and poorly subdrained and _ poorly 
aerated. In wet seasons the water table is near the surface. 
The compact wet soil favors the growth of pioneer forms such 
