574 BRITTON: VEGETATION OF THE 
structed for the purpose of keeping either sand or snow from blow- 
ing upon the tracks, is banked on its west side by a sand drift of 
half its height. Here the west winds are chiefly instrumental in 
the shifting, and on the bank of the river much of the finer sand 
has been removed by it. Slight shifting by winds also occurs on 
the North Haven tract. Heavy showers, upon the sand where 
the ground is not perfectly level, cause temporary erosion, by the 
surface water on its way to lower levels washing away the sand.in 
its path. At Montowese such water goes into the river, but the 
preparation of the railroad-bed across the North Haven tract 
necessitated some cutting and filling and excavations were made 
in the sand for filling material. These excavations give the sur- 
face waters a chance to reach a lower level and channels are cut 
in the sand. Ina clay formation such channels are deep with 
steep banks but in loose sand they are very shallow with widely 
sloping banks because the soil particles will not hold together. On 
the banks the winds also strike with greater force than on the 
level and several trees are left with exposed roots from the com- 
bined effect of winds and washing away of the sand (see pl. 25; c). 
Sort AND MoIsTURE 
It has already been mentioned that edaphic factors (?. ¢ soil 
conditions) are chiefly responsible for the barren state of these 
areas. The soil is mostly sand of medium fineness, or gravel con- 
taining pebbles, an inch or so in diameter in some places, of which 
broken red sandstone forms a part. This formation is called drift 
and is of glacial origin. It is probably the deposit of the water 
from the melting glacier and not the moraine. No chemical 
analyses were made to determine the fertility of the soil of these 
desert regions, but during the seasons of 1898 and 1899 the Con- 
necticut Agricultural Experiment Station conducted some expert: 
ments with forage plants near the Montowese railroad station only 
a short distance from the barren area. The ground used in the 
tests had formerly been cultivated, but was neglected for many 
years, and the soil contained only .og of one per cent. of nitroge”” 
It is probable that this soil also has small quantities of phosphor 
acid and potash as is the case with other similar soils. But 4 
leguminous plants are able to obtain nitrogen from the aif, ee 
