Bulletin 3. The flora of the Raritan Formation, 1911 - State of New ...

I8 THE RARITAN FLORA.
contemporaries of the huge and uncouth reptilia, the Dinosaurs,
Mososaurs, etc., which have long since vanished.
In leading np to a consideration of the Raritan formation,
we need not go back farther than the dOse"of the Triassic period.
After the deposition of these Triassic sandstones and shales
with their accompanying intrusions and extrusions of iga_eous
rock, the whole'region was elevated (the post-Triassic uplift).
I The rising land was immediately subjected to erosion, which
went on during the whole of the Jurassic and Lower Cretaceous
periods urttil at length the surface was essentially a vast plain,
the S_:hooley peneplain, as it is called. At some time abo.ut "
the close of the Lower Cretaceous there was a subsidence, or
warping, of this Schooley plain, and deposition along its eastern
flank succeeded erosion. What remains of these sediments now
constitute the Raritan formation of the Coastal Plain, its outcrops
forming the western border of the latter. Its strata, diD
ping to the southeast, are successively overlain by younger sedi-
• ments so that in wells, like that at Asbury Park, several hundred
feet of more recent materials are passed through before the
Raritan clays and sands are encountered by the driller.
DESCRIPTION.
The Raritan formation is made up for the most part of aIterhating
beds of clay and sand, with local lignitic deposits and
gravel. They vary greatly horizontally, as well as vertically,
so much s_ that the different na_em,berswhich are reasonably well
defined in Middlesex County cannot be traced with any degree of
assurance to the southwest. The clays are of various kinds,
ranging from arenaceous, pyritiferous, at times laminated and
lignitic clays, suitable only for the manufacture of common brick,
to almost white, massive, high-grade fire clays. All of the clay
beds are lcntjcular and some thin out and disappear in comparatively
short distances. The sands are equally variable, some are
sharp, nearly pure quartz, others are highly micaceo_s or lignitic
or arkosic_ and cross-bedding is frequemly seen. The materials,
as a whole, in both their character and rapid lateral
variation, are just such deposits as would probably be found
NEW JERSEY GEOLOGICAL SURVEY