of the North American Ice-Sheet. ‘201 
others of equal size are seen close to the road in Setauket vil- 
lage. The largest block yet found on Long Island lies much 
farther west, at about a mile southeast from Manhassett, and is, 
according to measurement by Mr. Lewis, fifty-four feet long, 
forty feet wide, and sixteen feet high. — 
is later moraine is separated six to ten miles, on Long Isl. 
and, from that formed at the extreme line reached by the ice- 
sheet, and the area between them is occupied by extensive 
plains, the Peconic Bays, and Shelter Island. This series of 
plains resembles that of southern Long Island, in that both 
slope southward from terminal moraines on their north side, 
ate vary. from one to two or three miles in width, having a 
eight from 100 to about 150 feet above sea. Their greatest 
altitude appears to be at East Northport station. Here they 
pass beyond the north spur of the Dix Hills and expand to the 
south, attaining a width of five miles, which continues without 
much variation to Riverhead. In Smithtown considerable por- 
tions of these plains have been removed by the erosion of 
Streams since the Glacial period. Their height along their 
north side here and in Brookhaven is 150 to 100 feet above 
sea, from which the general slope southward is about ten feet 
to the mile. Near the east line of Brookhaven is a notable 
Series of ponds, reaching four miles, and lying in depressions of 
one of the old lines of drainage. These are called the West 
Row Ponds, and are known in their order from north to south 
as Long Pond, Big and Little: Tar-kiln, Pease’s, Duck, Sandy, 
Grass, and Jones’ Bote. extending to the Peconic River at a 
mile west from Manorville. Two miles eastward in Riverhead 
are the East Row Ponds, a similar series, including in the same 
order the two Jackson Ponds, Ice, Worthington and Fox Ponds. 
Northeast from Fox Pond isa tributary series, including Sand, 
Mud and Cranberry Ponds. Several other valleys, not con- 
taining ponds and of similar character with those of the south- 
ern plains, extend southward from the vicinity of Baiting Hol- 
low and Northville. On the north branch o the island these 
Plains diminish from four miles to about one mile in width, 
their height being sixty to thirty feet at the north, from which 
1ey slope to the shores of Peconic and Gardiner’s Bays. The 
hilly character of Shelter Island, which varies from 50 to about 
180 feet in height, being composed of stratified sand and gravel 
