ALLUVIAL DIVISION. 
29 
Rockaway neck is the only locality west of Southampton, where the upland of Long Island 
approaches near the alluvial beach. The land through this distance is increasing in area by 
constant depositions. The beach at Far Rockaway, and for many miles east and west, is 
undergoing constant local changes. The surf often washes away several rods in width, 
during a single storm, and perhaps the next storm adds more than had been removed by the 
preceding. The sea frequently makes inlets through the beach to the bays and marshes, and 
as frequently fills up others. 
The inlet to Rockaway bay, called Hog-island inlet, is continually progressing westward 
by the oblique action of the surf driving the sand, gravel and shingle in that direction. The 
deposit of these materials on the west end of the island beach tends to obstruct the inlet to the 
bay; bat the strong tidal current, during the flow and ebb of the tide, washes away the east 
end of Rockaway beach, as rapidly as the other forms: the inlet is thus kept open. Mr. 
Edmund Hicks, of Far Rockaway, has been long a resident here, and to him I am indebted 
for the fact just mentioned. He knows Hog-island inlet to have progressed more than a mile 
to the west within fifty years. 
New inlet is the main inlet from the ocean to the great South bay. It was formed during 
a storm not many years ago. 
Crow inlet and Jones’ inlet are undergoing changes analogous to that of Hog-island inlet. 
Barren and Coney islands are a part of the Great South beach of Long Island. 
Coney islar.d has already been referred to as washing away by the waves and marine cur¬ 
rents. It is alluvial, with the exception of a very small tract of tertiary, and is separated from 
Long Island by a small creek which winds through the salt marsh. Mr. Wyckoff, who has 
lived for many years on the island, remembers when this creek was a broad inlet; but it has 
been gradually filled up with silt, organic alluvions, and drift sand, until it is reduced to its 
present size. 
It has been remarked, that some of the islands and spits of the Great South beach are con¬ 
tinually receiving accessions on the west end. Long bars form in the prolongation of the 
beaches, so that each successively overlaps the other, the entrance being from southwest to 
northeast: they project in echellon, from the east-northeast to west-southwest. Many of 
these shoals, formed at some distance from the land, are gradually driven landwards by the 
surf, and make new additions to it. 
During the investigation of the various alluvial causes now in action on this coast, we 
easily trace the origin of this great sand-beach of more than one hundred miles in length.* 
The encroachments of the sea on the east end of Long Island, were discussed in my first 
annual report. Vast masses of the cliffs of loam, sand, gravel and loose rocks, of which Long 
♦ In Europe, there is no deposit of a similar character to compare with it in extent. It was hoped that the topographical maps 
of Long Island might be completed and published by the Government, in season to make use of them for illustrating in detail the 
minute geology of this interesting region. The map of Long and Staten islands appended to this report is more accurate by far 
than any maps of Long Island that have preceded it; but the coast survey maps would, for accuracy of topographical detail, leave 
nothing to be desired. 
