The Ice-Sheet in 2i'arra(jansett Bay. — Woodirorfh . 155 
dicated on the original atlas sheet. The deposit appears to 
be a detrital cone built at the front of the ice by a supergla- 
cial or tunnel stream. The morainal terraces about its north- 
ern slopes are marked and form a group of two. East of 
this deposif is another similar smaller deposit not so readily 
diagnosed. Eastward in this line a low morainal accumula- 
tion extends southeastward on the south side of Allen's Har- 
bor, probablj' the extension of this ice-front. 
THE POTOWOMUT STAGE. 
North of the preceding aTid skirting the southern or right 
bank of the Potowomut river is a series of sand-plains, with 
a distinct ice-contact or moraine topography, from the sum- 
mit-line of which the surface of the deposits slopes southward. 
The opposite or northern bank of the river is uniformly lower 
and moulded at various points in the form of the frontal or 
marginal topograph}^ of a later series of sand-plains, the 
Greenwich Cove stage of this report. The estuary of Poto- 
womut river is simply the deeper submerged portion of tiie 
depression at the head of the frontal deposits of the Potowo- 
mut stage. The ice-front of this stage formed a loop north- 
ward around the till-covered upland just west of Allen's 
Harbor. At two points the Potowomut line of frontal accu- 
mulations is broken by streams flowing inward to the fosse or 
depression at its northern base. The Potowomut river flowing- 
northward in a line with Greenwich cove, turns abruptly' to 
the southeast as soon as it has passed through, and where it 
again turns to the northeast it receives another tributary also 
flowing to the nortli. The sand-plain between the tw'^o north- 
ward flowing streams is in large part boulder-strewn, as if by 
an advance of the ice-sheet after the completion of the sand- 
plain. The northward flow of the small streams toward the 
retreating ice-front is believed by the writer to be due to the 
occupation of this part of Narragansett bay by standing 
ice. 
GREENWICH COVE STAGE. 
Greenwich cove" is an elongated indentation of the coast- 
line to the southwest, the sides of which are typical ice-con- 
tacts, except where the undercutting of the slope by wave 
action has destroyed tlie original glacial topography. Between 
tlie ice-tongue wliich filled the cove and the hills on the west, 
