THE POSTGLACIAL CONNECTICUT AT TURNERS FALLS 467 
floods from the melting ice on the hills, checked here in their 
steep descent, and arriving largely through the valleys of the 
Millers and Falls rivers. 
FIG. 4. 
Under the sands are clays observed at various levels from 
190 to 270 feet above the sea. They rest on the glaciated 
sandstone, are beautifully stratified, occurring mostly in half- 
inch layers, greenish and butter-like, with gritty sandy layers 
from two to four inches thick between. They are exploited for 
brickmaking at several points in the escarpment around Mon- 
tague Plain. 
In the clay pits beside the track at Greenfield the stratifica- 
tion is clear and horizontal as elsewhere. but the upper surface 
of the clays, as revealed by the workmen, is uneven and not 
parallel to the stratification, while the transition from clay to 
