Bulletin 23. Potash in the Greensands of NJ, 1923 - State of New ...

GEnErAL I_EATrY_ESOF T_E I_EPOSlTS. 7
:_ The Coastal Plain in New Jersey has long been cited as an example
•_ of the bolted type, with inner lowland, in-facing slope, out-facing
slope, and outer lowland, caused by the erosion of gently dipping
strata of somewhat unequal degrees of coherence or hardness and by
the development of drainage upon those strata. The marl beds
lie near or at the top of the in-facing slope and thus relatively near
Delaware River, which occupies much of the inner lowland, and
their drainage in general flows toward that lowland, producing the
favorable conditions for water transportation previously noted.
G_UCONITE-B_RI_G AND ASSOCIATED FOR_ATIONS.
Age and general se_uenee.--The glaueonite beds of New Jersey_ with
one exception, are of Cretaceous age. Glaneonite occurs locally,
however, in some of the overlying Tertiary and Quaternary beds as a
result of the erosion and redeposi_ion of Cretaceous material. At
some places, as for example, at Somerdale, about 9 miles southeast of
Camden, these reworked glauconite beds overlie beds of Cretaceous
greeusand and may readily be mistaken for them. Closer inspection
of the reworked material reveals pebbles scattered through its mass
and usually a more or less well-defined layer of pebbles at its base.
The Cretaceous formations are described below and are shown with
the overlying Tertiary formations in the accompanying table2
Cretaceous and _er for_uztions _n Coastal Plain region of New dersey.
Thick-
System. series. Formation. ne_
(feet).
Recent. Beach san4 and gravel, marsh deposits, and alluvium.
Quaternary. gape May formation ......................................... 0-20
PleistQcene. Pen_auken _orma$ion ........................................ 0-20
Bridgetoa formation ......................................... O-_
Beacon Hill gravel ............................................
-Unc_olormtt y?_
Tertiary. Miocene(?), Cohalmey sand ............................................... 100-256
-Uncom*ormity--
_iocene. Kirkwood formation ......................................... 10o
-Unconformity--
Eocene. Shark River m_rl ............................................
-Unconformity
)i
YIanasquan marl .............................................. 25
R_r, eoeas group:
Vinee_town sand ......................................... _70
norlmrstowI1 marl........................................ _0
Monmouth oup:
Redba_sand
top.
_th Tin_onsand meml)er (10-29 feet) at 010
Navesi_ marl ............................................ 25-4(1
_ount Laarelsand ........................................ 5_o0
Cretac_atts, Upper Crata_
ceous.
_a_awangroup:
Weaxonah sand ........................................... 2_Z5
Marshalltown formatiun ................................... 30-35
_nglishtown saxad......................................... 20-100
Woodbury clay ........................................... 50
Me_ehantville clay ...................................... fi0
Magothy formatlQn .................... • ....................... 25-175
-Unconformity--
Rarit an formation ............................................. 150-250
Gre_t tmc_r_formity.
J Table and deserip t ions e_m_lled chieily from New Jersey Geol. Survoy Bull 14,1915; n, s. G¢oL survey
Geol. Atlas, Philadelphia foli_ (No. 162), 1909,and Trenton folio (NO. 167), 1_9.
NEW JERSEY GEOLOGICAL SURVEY