Development of the Vegetation of New York State 53 
cutting well defined streamways which converge to form the 
Delaware, Susquehanna and Alleghany drainage systems 
cutting into the plateau from the south. The Hudson-Cham- 
plain valley is a dissection to near sea level, cutting the 
State across from south to north. At the northwest we should 
plane down to fit the Ontario Lake basin, thus constructing 
the low, level plain bordering that lake and extending east- 
ward as the Iroquois basin including the Oneida Lake basin. 
The Mohawk is, then, a low and mostly broad valley a few 
hundred feet above sea level and joining the lake basin 
country with the Hudson valley. This cut severs the 
southern or Alleghany plateau from the Adirondacks. The 
lake basin country is continued around the north of the 
Adirondacks as a broad, low plain, the St. Lawrence valley. 
From the Iroquois-Ontario basin, cuts will be made back into 
the Alleghany plateau constructing the Genesee drainage 
and the Finger Lake region of narrow north-south valleys 
opening out upon the lake basin plain. Finally, dissection 
of the Adirondack plateau would include sharply defined 
channels such as the Black, Oswegatchie, Raquette, Saranac, 
Ausable and upper Hudson rivers and other masked or 
poorly established drainage features which may represent 
the effects of glacial filling. See Fig. 1, relief map of New 
York. 
The extremes of climatic conditions as thus created, added 
to latitude and ocean influence factors, may be expressed by 
a contrast between Staten island and the summit of Mount 
Marcy. Unfortunately, actual figures are not available for 
Mount Marcy, but so far as growing season is concerned, 
where absence of frost is taken as a criterion, the summit of 
Marcy would scarcely have any growing period at all for 
warm climate plants which reach their northern limit at the 
mouth of the Hudson, for it is doubtful if any month is 
wholly free from frost. Certainly the growing season for 
even the cold resisting arctic flora of the summit can scarcely 
exceed three months, while around New York bay the 
frostless period covers 200 days. But this doesn’t express 
the full force of the difference between these two extremes. 
One should know the daily range of temperature in summer 
