188 The American Geolo(/i,sf. Marcli. 1895 
CORRESPONDENCE. 
TiiK I'l's AM) Downs ok I.oncj Island. Tlic liilr Klias Lewis, Jr.. of 
JJrooklyn. snmi' ycurs muo piihlislicd a ))a])r'r in tlic Anirrifaii .lounial of 
ScifMici' will) llir al)(>vf litjr. 'I'lic uj>.\ and (hur/i.s. Iiowcxit, rather 
referred to I lie oseijiations of our little island, Ihaii to the Ilig/is and 
7/(>»Y.y as they would say in Scolhuid. Professor Afjassiz in a letter 
to Sir Charles Lyell, in referrin>;- to the coral reefs of Florida, says: 
"There are several concenlrie reefs separated by dee]) channels: the 
peninsula itself is a succi'ssion of such reefs, the l>]\-er^la(h's heini;' the 
filled in chaiuiels, while the hummocks were formerly little intervening 
islands, like the mangroNe islands in the ])resent channel."' Professor 
Agassi/ was the first, I l)elie\e. to notice these ])henomena connected 
with the Florida reefs, and 1 was much interested in reading tliis ac- 
count of them as published in his "Life and Corres])ondence," as 1 had 
begun to discover similar phenomena in the make-up of Long Island. 
Starting with the sea-beaches along the Atlantic border, we have, be- 
hind them, the bays with their deep channels and reef-like islands. The 
island itself is a succession of ridges and valleys, the bi'ds of old rivers 
corresiMjnding to the everulades of Floriila. while the little kames and 
hummocks in these depressions wen> formerly little islands like those 
we see in Jamaica bay. Of course, these upi* and doirns of Long Island 
are not the same in origin as the Florida reefs, yet the similarity be- 
tween them is very striking, and both exhibit system and orderly ar- 
rangement, showing that even the drift formati(jns ;ire not the fortuit- 
ous and disorderly things some have supposed. 
At first there would seem no connection nor relationship l>etween the 
moraines on the north side of the island and the line of beaches fring- 
ing the ocean, but 1 think it can be shown that the streams of water 
that assisted in forming one gave birth to the other. That is, it seems 
evident that jjowerful subglacial currents flowing from the main land 
plowed out the bay indentations on the north side of the island and gave 
form at least to the kame-moraines that constitute the most prominent 
range of hills on th<' island. It is characteristic of these morainic 
ridges to diminish toward the south, and the material composing tlu-m 
becomes finer in the same ratio. The streams that broke through the 
first moraine, and were contl\ient, generall\ con\eri;ed south of this 
ridge, forminu- what is now a jilain-valley: l)ut they did not end here, 
but continued to braiu'h otf to the southeast and southwest. In their 
ramifications the hillocks were formed already referred to. These 
streams also penetrated what is known as the backbone of Long Islaiul 
— the terminal moraine, of geologists — in the same ramifying way: and 
although these old channels are not so easily traced, yet the lines of 
drainage can be recognized along the kettle-hole dejjressions. and as 
they issue from the front of the moraine— I cannot say from the front 
of the ice-sheet, for 1 am inclined to believe that the surface part at 
least, of the glacier, extended farther southward- the same system of 
ramification was C(jntinued. and these old channels can now be traced 
