REPORT OF NEW JERSEY STATE MUSEUM. 
17 
and the outcropping sheets of trap, or other hard layers of rock 
constitute the ridges. Since this zone of New Jersey has little con¬ 
tinuation to the south, its characteristic topography has little de¬ 
velopment m that direction, though it extends somewhat beyond 
the Delaware. But to the northeast, in southern New England, 
the features characterizing the Piedmont plain of New Jersey 
reappear. 
In the fourth topographic province, the Coastal plain, both the 
relief and the average elevation are less than in the preceding zones. 
Its highest point in New Jersey does not reach an altitude of 400 
feet, and since it descends to sea level about the borders of the 
State, the figure representing the greatest altitude also stands for 
the total relief. The larger part of the Coastal plain as it occurs 
m New Jersey may be looked upon as a plain, highest toward its 
middle and lowest about its margins, the surface of which lias been 
trenched by the streams which flow over it. Within the province 
as a whole, the elevations and depressions have no prevailing direc¬ 
tion. While abrupt ridges, comparable to those of the morc^ north¬ 
erly portions of the State, are absent, there are steep, isolated hills, 
like Mount Holly, Arney’s mount, the Mount Pleasant hills and 
the Navesink highlands, which, though of no great height, are yet 
striking topographic features. The formations are chiefly of unin¬ 
durated material—sands, clays, marls, &c.—and the beds dip. at a 
low angle to the southeast. Topographically, the Coastal plain is 
less distinct from the Piedmont plain, than the Piedmont plain is 
from the Highlands, or than the Highlands from the Appalachian 
zone. The line separating the two zones would best be drawn, 
when it is necessary to draw it at all, along the Fall line already 
defined. More than half the State belongs to this zone, which has 
its greatest development farther south, and but slight representa¬ 
tion to the north. 
These four divisions are sharply distinct from the standpoint of 
geology, and, likewise, in their type development, from the stand¬ 
point of geography. Yet sharp, lines separating one topographic 
sub-province from another cannot everywhere be drawn without 
c 01n » vio, l 0nee to- the facts. This is especially true of the third 
and fourth divisions referred to above. Furthermore, there is 
some, basis in topography for a further sub-division of the provinces 
outlined above, and these minor sub-divisions would, in some cases, 
be as distinct from one another as the larger divisions. 
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