Correftjxmdence. 189 
The study of the drift phenomena, on the west end of the island led 
me to suspect that the sand dunes in question were formed by subglacial 
■streams issuini^ from the front of the ice-sheet that stretched along the 
Atlantic border during the Ice Age. It was not until last July, however, 
that I had an opportvuiity of visiting the place in person, and it was 
gratifying to find my conjecture confirmed by actual observation. The 
sand dunes referred to are reallj' kame formations. This can be seen at 
a glance by any one familiar with glacial phenomena. Similar formations 
occur along the whole extent of the south side of the Island; but in 
general they are not quite as well defined as those at East Hampton. 
The so-called sea beaches in front of our bays, as at Rockaway, Great 
South beach, etc., are the same in origin. This hardly seems i)ossible, 
but the more this phenomenon is examined the more evident the fact 
becomes. There is a beautiful system about these beach or kame 
formations, and their study had led me to suspect, some years ago, that 
the system extended for miles beneath the w-aters of the sea, and it was 
very gratifying to find this view partially confirmed by Prof. Agassiz. 
In his Life and Correspondence, edited by his wife, page 448, in a letter 
to Elie DeBeaumont, he says: " Mr. Dezor recognized all the modifica- 
tions of the osars of Scandinavia. The deposition of the osars, as seen 
here, is evidently due entirely to the action of the waves, and their 
frequency along the coast is a proof of this. In a late excursion with 
captain Davis, on board a government vessel, / learned to vndersfttnd the 
mode of formation of the subinirrtne dikes bordering the roant at various dis- 
■tances,rrhir7i would he osars were they elerated.'''' The italics are our own, 
as the statement seems to confirm what I had conjectured, but I think 
Prof. Agassiz is in error in regard to their origin. Prof. G. F. Wright 
and others who have studied these kame -deltas along the southern front 
of the terminal moraine, in New England, as well as in Long Island, could 
see that these formations — osars — as Prof. Agassiz calls them, are not 
the result of wave action, but are due to subglacial currents issuing 
from the front of the glacier. At Moutauk, for a distance of some 
twelve miles, the waves of the ocean break directly upon the base of 
the ridge or terminal moraine. At this point the whole south side of the 
Island has become submerged, and we can readily imagine what the 
floor of the ocean is like some distance from the present shore line. 
The sea is evidently gaining on the land along the whole extent of the 
Island, and it is only a question of time when the whole plain, south of 
the central ridge, will be washed away, unless something is done to 
check the inroads of the sea. If this invasion of old ocean has been 
going on for the past ten thousand years, the south side of the Island must 
have been at one time much more extensive. There is evidence to show 
that at South Hampton, two hundred years ago, the shore line was at 
least half a mile farther south. At the same rate of erosion four hun- 
dred years would bring the waters of the sea over the so-called sand 
dunes at East Hampton, and these osars or kame-deltas would become 
the submarine dikes referred to by Prof. Agassiz. It is true that the 
waves of the sea would somewhat modify the contour of the plain in 
