NJGS - Bulletin 61-I. The Cretaceous Fossils of NJ - State of New ...

CRETACEOUS FORhl:\TIONS OF NEW JERSEY1
by Horace Q. Richards
Lower Crataceous. No deposits of Early Cretaceous age are known
to crop out in New Jersey. The three formations of the Potomac group,
the Patuxent (predominately a sand), the Arundel (clay) and the
Patapsco (predominately a sand) are widely distributed in the area
immediately to the south, but have not been reported from the surface
in New Jersey. There is a difference of opinion regarding the age of the
Potomac group. It has generally been placed in the Lower Cretaceous
on the basis of fossil plants. More recently, Anderson (1948) and
Spangler and Peterson (1950) placed the Patuxent in the Lower Cre-
taceous and the Aruudel and Patapsco in the Upper Cretaeeous. On a
reexamination of the fossil plants, Dorf (1952) rejects the Upper Cre-
taceous dating and places the entire group in the Lower Cretaceous.
Dryden, (quoted by Johnson and Richards, 1952 p. 2153) on the basis
of heavy mineral studies, states that the lower section of the deep well
at Salem, N. J. penetrated into the Lower Cretaceous. This.is the only
record of the Lower Cretaceous in New Jersey.
Raritan formation. The Raritan formation was first named by Con-
rad (1869, p. 360), but was redefined and restricted by Clark (1904) to
exclude those beds now assigned to the Rlagothy. The Raritan formation
consists chiefly of alternating layers of sand and clay. The clays are
of various colors from nearly white to steel-blue, red and black; some
beds are sandy and at times considerable quantities of pyrite and lignite
are included. Some of the sands are nearly pure quartz, while others
are micaceous, liguitie or arkosic.
In Middlesex County, the Raritan formation has been divided into
seven beds but it is probable that they are rather local in distribution.
The older and newer termiuologies are given below:
Kummel and Knapp, 1904 Barksdale, et al, 1943
7. Amboy Stoneware Clay Amboy stoneware clay (top)
6. Sand Bed No. 3 Old Bridge sand member
5. South Anlboy Fire Clay South Amboy fire clay
4. Feldspar-Kaolin Sand Bed Sayreville sand member
3. Woodbridgc clay Woodbridge clay
2. Fire Sand No. 1 Farrington sand member
1. Raritan Fire and Terracotta Raritan fire clay (bottom)
(Potter's) Clay
In the vicinity of Raritan Bay, the Raritan formation can easily be
distinguished from the overlying Magothy, but this separation is much
more difficult farther to the southwest. Consequently many geological
maps combine the two formations.
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'This chapter L, partly adapted from WeUer (1901). Lewb md Kumrnel (1940). S~anslcr
and Petenon (19501 and Johnson and Richard. (1962).
NEW JERSEY GEOLOGICAL SURVEY