1894. | NEW YORK ACADEMY OF SCIENCES. 127 
were struck. Assuming the inclination to be the same through- 
out, however, it may be readily calculated at what depth the cre- 
taceous clays ought to be reached. Thus at Hempsted, seven 
miles from the theoretical southern limit of the clay outcrop, 
this outcrop should be at a depth of 350 feet; at Patchogue, 
1,000 feet ; at East New York, 50-100 feet, &c. It is probable, 
however, that close to the margin of the moraine the erosion was 
so great that the original outcrops were removed to a consider- 
able depth and the place formerly occupied by them filled up 
with water assorted material from the moraine. In this con- 
nection the record of a deep well section at East New York, 
which I am fortunately able to show in miniature, is of great 
significance. For the first 149 feet only superficial sands and 
gravels, colored with oxide of iron, were encountered; below 
that, clay with lignite and white sand began to appear. <As no 
material representing the marl belt was met with, we must as- 
sume that this was either normally absent or else had been 
entirely eroded and replaced by the superficial sands and gravels. 
Following a similar course of reasoning the cretaceous clays 
would not be found outcropping east of Lloyd’s Neck and what- 
ever clays might be found in place to the eastward of that 
locality ought to represent tertiary or post-tertiary horizons. 
As far east as this locality the cretaceous age of the clays or the 
material derived from them has been proven; further east than 
this the proof of their age yet remains to be discovered. Theo- 
retically the moraine from here eastward ought to contain eroded 
material representing cretaceous, tertiary and post-tertiary strata, 
and eventually proof of the presence of such material ought to 
be forthcoming. 
Suppose we next consider the significance of the moraina 
material in general. 
As is well known, there are two forks or branches to the mo- 
raine on Long Island. The one farthest south forms Montauk 
Point, and its vanishing remains further eastward are repre- 
sented by Block Island, Martha’s Vineyard and Nantucket. The 
one farthest north forms Orient Point and extends similarly 
to Plum Island, Gull Islands and Fisher’s Island. They join 
at about the vicinity of Port Jefferson and from thence west- 
ward form a single range of hills. The north branch was con- 
sidered by Upham* to represent a second terminal moraine, and 
it may be seen that this supposition is strongly emphasized by 
some of the facts which I have noted. Thus the bulk of the ma- 
terial which formed the old coastal plain would have been eroded 
*Upham.—Warren, ‘‘Terminal Moraines of the North American Ice-Sheet.” 
Am. Journ. Sci. 18 : pp, 200-209 (1879). 
