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

I6 THE RARITAN FLORA.
IlL THE RARITAN f:ORNATION.
:_'Troovc_'or_,.
New Jersey has been divided into four physiographic zones.
The oldest of these, known as The Highlands, dates from. remote
geological time, its constituent rocks consisting for the
most part of highly metamorphosed crystalline schists. This
zone occupies a broad beit across the northern central portion
of the State, and includes the eastern part of Sussex and Warren
counties, the northern part of Passa:ic Connty, most of Morris
County, and the northern part of HunterdorL County. It corresponds
in age with the Piedmont Plateau of the states to the
southward, and is represented by the basal part of the section
in Figure I. Following the emergence of this belt of land in
early gedlogical times, sediments were laid down along its western
borders, and it is these Paleozoic sediments, since much
folded, which today make up the Appalachia*z zone, comprising
the Kittatinny valley and_ mountain of the northwestern portion
of the State, in Sussex and Warren counties.
The third and next younger zone, which is known as the
Piedmont Plain, was laid down on the eastern flanks of the Highland
area at a much later date. Topographically, it corresponds
to the Piedmont Plateau region of the states to the southward,
but consists, in NeW Jersey, of much younger rocks of late
Triassic age, and includes roughly all or a part of Bergen, Passaic,
Essex, Union, Somerset, Middlesex, Hunterdon, and Mercer
counties.
The fourth and yojmgest zone, known as the Coastal Plai;_,,
includes the remainder of the State and extends from the present
coast inland to the exposed area of the Triassic rocks. It is
made up' of unconsolidated and undisturbed sediments, ranging
in age from Cretaceous to Recent.
A glance.at the geological column shown in Figure t, which
is drawn approximately to scale, will show the relative position
NEW JERSEY GEOLOGICAL SURVEY