SUMMER EVAPORATION INTENSITY AS A DETERMIN- 
ING FACTOR IN THE DISTRIBUTION OF 
VEGETATION IN CONNECTICUT 
GEORGE ELtwoop NIicHOLSs 
For an area of its size, the state of Connecticut exhibits con- 
siderable diversity both in topography and in vegetation. From a 
geographical standpoint three well defined regions may be recog- 
nized: the Western Highland, the Eastern Highland, and the 
Central Lowland. The surface of the Highlands is for the most 
part exceedingly rugged, and in the northern part of the state, 
especially in the Western Highland, elevations of 300 or more 
meters are common. The Central Lowland is characterized, on 
the whole, by its gentler contours and lesser elevations. Over large 
areas here the surface is almost level, while the hills, as a rule, 
seldom reach a height of more than 75 meters. Exception to this 
latter statement, however, must be made in the case of the trap 
ridges which traverse the Lowland from north to south, dividing 
it lengthwise into two sections. In topography these conform with 
the Highlands rather than the Lowland. Geologically, as well as 
topographically, the Highlands contrast sharply with the Lowland. 
Except for limited areas of limestone, the Highlands are underlain 
by granites, gneisses, and schists. The Lowland rocks are sandstones 
and shales. Throughout the state, however, the underlying rock 
is in large part covered over by a mantle of glacial drift which in 
places is more than 50 meters in thickness. 
The vegetational differences between various parts of Connecti- 
cut are not so sharply or clearly defined. Moreover, the situation 
is complicated by the fact that practically the entire area at one 
time or another has been deforested, while a large share of it is at 
present under cultivation, so that the nature of the original plant 
covering has become more or less modified. Considering the vege- 
tation of the state in its entirety, the ultimate climatic formation 
is a forest dominated by various deciduous trees and hemlock. Of 
the virgin forest scattered remnants are occasionally encountered, 
but for the most part the present woodlands are second growth. 
143] [Botanical Gazette, vol. 56 
