RESEARCH· ·1970·

Bi60
STRATIGRAPHY
TABLE !.-Stratigraphy of Long Island and Mattituck quadrangle
Long Island
Stratigraphy according to Fuller
(1914) (simplified)
Wisconsin drift
Hempstead Gravel
Member
Montauk Till
Member
Herod Gravel
Member
Jacob Sand
Gardiners Clay
Jameco Gravel (not exposed)
Mannetto Gravel
Mattituck quadrangle
Partial stratigraphy based on this
study
Wisconsin drift and other
post-Montauk deposits.
(Present, but not discussed
in this paper.)
Montauk Till Member of
Manhasset Formation.
.Manhasset
Formation
)
Contains
Herod Gravel } Jacob-
Member of Gardiners
Manhasset lenticular
Formation unit or
units
Jameco
Gravel
Mannetto
Gravel
}Not known.
the Cape May Formation in New Jersey (MacClintock
and Richards, 1936, p. 335). It seems unlikely that
these are the same.
Fuller's determination of age of the Gardiners Clay
was based in part on the presence of fossils reported
or found almost entirely in wells, indicating an interglacial
time; and in part on its position below the
Montauk Till, which was thought to be Illinoian. At
one locality near Red Spring Point in Nassau County,
now ( 1965) covered by slumped material, beds of darkgray
to black, organic-rich clay were observed to contain
shells. A collection was made from this locality
about 1955 and dated by carbon-14 methods as older
than 38,000 years B.P. (Swarzenski, 1959, p. 1084).
These deposits are strongly deformed, and probably
have been elevated by glacial pressures, or even actual
bulk transport. Also, Weiss ( 1954, p. 155-156) found
Foraminifera in supposed Gardiners Clay at a position
about 100 feet below sea level in certain wells drilled
at the Brookhaven National Laboratory. Weiss further
reported (p. 148) that he did not find Foraminifera
in the deposits of silt and clay exposed on the north
shore of Suffolk County (Long Island). The present
writer has examined a good many exposures of supposed
Gardiners Clay and Jacob Sand in eastern Long
Island, and has seen no macrofossils. Samples collected
by J. P. Minard in the fall of 1965 from localities
described in this report have been examined by Ruth
Todd, of the U.S. Geological Survey, and found to
contain no organic material. Records of some wells that
penetrate clay called Gardiners in western Long Island
indicate some sands that might represent Jacob Sand.
At many exposures, the Jacob is 30 feet or more th.ick,
and of distinctive very fine gvained lithology. This unit
is so pronounced that it ought to be a clearly recognizable
layer in well cuttings or samples.
The writer therefore concludes that the Gardiners
Clay, as identified on the north shore of Long Island,
is not the same as the Gardiners so named from well
records in western Long Island. Weiss (1954, p. 148)
concluded the same from purely paleontologic evidence.
The clay may not even be the same as that at the type
locality on Gardiners Island. It, together with the
Jacob Sand (whose type locality is wit4in the Mattituek
quadrangle), was deposited in shallow depressions·
on the surface of outwash from advancing ice of probable
Wisconsin age. These bodies are of local occurrence
stratigraphically, and of limited extent geographically.
If this is true, the Gardiners Clay cannot be regarded
as a marker bed in Pleistocene stratigraphy, even within
Long Island. There may be several units of similar
lithology, but of different ages. Just as the exposed beds
identified as Gardiners are related to advancing Montauk
ice, the clays penetrated in wells in western Long
Island may be related to an earlier ice advance.
In summary, the following possibilities present themselves:
(1) t~e- deposits in the Mattituck quadrangle
which were identified by Fuller as part of the Gardiners
Clay are the equivalent of the deposits on Gardiners
·Island and, hence, really are Gardiners Clay,
whereas the subsurface deposits in western Long Island
are not; (2) the subsurface deposits are equivalent to
the Gardiners of Gardiners Island, and the Mattituck
quadrangle deposits are something else; or (3) all the
deposits are different. At present, the writer considers
that the first possibility is more likely to be correct.
If so, the name Gardiners Clay should be retained for
these probable Wisconsin deposits, and a different
designation sought for the probably older subsurface
deposits of western Long Island.
REFERENCES
Fuller, M. L., 1905, Pleistocene geology of Fishers Island : Geol.
Soc. America Bull., v. 16, p. 367-390.
-- 1914, The geology of Long Island, New York: U.S. Geol.
Survey Prof. Paper 82, 231 p.
Kaye, C. A., 1964, Outline of Pleistocene geology of Martha's
Vineyard, Massa-chusetts, in Geological Survey Research
1964: U.S. Geol. Survey Prof. Paper 501-C, p. C134-C139.
MacClintock, Paul, and Richards, H. G., 1936, Correlation of
late Pleistocene marine and glacial deposits of New Jersey
and New York: Geol. Soc. America Bull. v. 47, No. 3,
p. 289-338.
Swarzenski, W. V., 1959, Ground-water supplies in Pleistocene
and Cretaceous deposits of northwestern Nassau County,
N.Y.: New York Acad. Sci. Annals, v. 80, art. 4, p. 1077-
1091.
Weiss, Lawrence, 1954, Foraminifera and origin of the Gardiners
Clay (Pleistocene), eastern Long Island, New York :
U.S. Geol. Survey Prof. Paper 254-G, p. 143-163.