of the North American Ice-Sheet. 91 
with that of the second terminal moraine, which lies at their 
north side. The probable origin, relation and significance of 
the drift deposits in central and southern Long Island having 
been now pointed out, similar explanations will be found appli- 
cable to their continuation eastward and to the like series of 
deposits farther north, so that little more than a plain descrip- 
tion of them will be required. ; 
Block Island, six miles long and three and a half miles wide 
in its south portion, presents the next segment of the extreme 
moraine, which appears with the characteristic features already 
described for Montauk, from which it is distant about fifteen 
miles to the northeast. The first account of this island, b 
Verrazzano in 1524, says truthfully that it is “full of hills.” 
Approximate heights of some of these are as follows: Beacon 
Hill, the highest point on the island, 210 feet above sea; hill 
one-fourth mile south, 205; Pine Hill, one-third mile north- 
west, 150’; Sandy Hill, near Grace’s Point, 105; Cherry Tree 
Hill, 140; Pilot Hill, 185; base of the south light-house, 152; 
Bush Hill, the highest in the north part of the island, 140. 
These are irregularly grouped, with many hollows containing 
onds and deposits of peat. Sands’ Pond is about 125; and 
resh and Mitchell’s Ponds, about 90 feet above sea. Great 
Salt Pond, which lies at sea-level, contains some 1,000 acres; 
the contour of its bottom is found by soundings to be ve 
—— like that of the adjacent land, its greatest depth being 
eet. : 
ark, — and 
full of rock-fragments, twenty-five feet, reaching to the upper 
edge of the beach. At 200 to 400 feet southwest from this, 
gravel at top, with numerous bowlders; dark clay, fifteen feet ; 
yellow sand and coarse gravel with irony layers, twenty feet ; 
typical lower till, unstratified, about forty-five feet, to the beach. 
At the light-house the cliffs are 150 feet high, and consist of 
gravel and sand, 
-fourths of the whole. 
pebbles up to one foot in diameter, mostly angular, often occur 
in thick beds of this dark clay; and occasional bowlders, up to 
two or rarely five feet through, are embedded in all these 
