156 The A Hierican Geologist. September, 1S96 
coarse gravels were deposited, now in tiio form of a terrace, 
on which the city of East Greenwich is partly built. Poto- 
womut Neck and the large sand-plain south of Potowomut 
station belong to this stage. 
This cove marks the site of the last deposits about the 
tinger-like projection of ice which lay along the line of the 
railroad between East Greenwich and Wickford Junction. 
The gradual shrinking of this mass is clearly brought out by 
the successive stages of deposits corresponding to the frontal 
and lateral moraine terraces of Gilbert's nomenclature which 
lie in this field. Frontal lobes are distinctly marked in the 
small sixty-foot plain at the southern end of Greenwich Cove. 
On the east of this plain is a distinct trough from the southern 
end of the cove to the Potowomut valley. This trough is a 
continuation of the line of the stream which enters the cove 
from the northwest. The lower course of this stream is ter- 
raced, showing that it has cut down its bed since the construc- 
tion of the Greenwich Cove plain and terrace. The evidence 
from this locality appears to the writer to indicate that the 
trench above described marks the extended course of the 
existing stream at a time when the block of ice standing in 
the cove forced the waters from the upland to pass out across 
the sand-plain by obstrucrting drainage northward into the 
present cove, and so into the bay. Later, when the ice melted 
out of the cove altogether, the drainage was northward, as at 
present. The evidence which supports this conclusion also 
carries with it the necessary implication that the Greenwich 
Cove sand-plains were at least as high above the sea-level at 
the time when this trench was formed, as they now are. The 
relative bights of the land and sea are again considered at 
the end of this paper. 
The stages of retreatal deposits ending in Greenwich cove 
illustrate the shrinkage and final disappearance of a tongue 
of the ice and its change from a broad east and west mass to 
a narrow block or tongue with a long north and sout4i exten- 
sion, such as characterized the ice-blocks which gave rise to 
the steep-sided ponds in sand-plains. In this nearly ideal 
development of sand-plains and terraces, Greenwich cove 
stands as the ultimate stage, with lateral terraces facing each 
other across a depression, occupied by the waters of the sea. 
