THE NEWARK SYSTEM OF NEW JERSEY 559 
constant in dip and strike, sa that the monoclinal structure is 
most marked in these belts. The Brunswick shales are marked 
by shallow folds, some covering an area of several square miles. 
These combined with a fortunate arrangement of faults, have 
greatly increased the area of red shale outcrop, and so permitted 
the formation of the broad, rolling lowland, so characteristic of 
the greater part of the Newark system.’ 
Faults —The location of the most important faults by which 
these rocks are traversed is shown on the map. The Hopewell 
fault, heretofore unrecognized, extends in a sinuous course from 
near the Delaware River by Harbourtown, Hopewell, and thence 
along the foot of the Sourland plateau escarpment, passing a 
little west of Flagtown station on the Lehigh Valley Railroad. 
It probably crosses into Pennsylvania, but its exact location at 
the Delaware River could not be definitely determined. 
The evidence of faulting along this line is as follows: (a) 
the repetition of the strata; (0) crushed and contorted shales, 
slickensided surfaces or overthrown dips at every exposure along 
or near the fault line; (c) diversity of structure, dip and strike 
—on opposite sides of the fault line; (d) contrasts in topog- 
raphy and the termination of ridges at the fracture. The repe- 
tition of the strata has already been alluded to in describing the 
rocks. The map shows how the Stockton, Lockatong and 
Brunswick beds are repeated, the beds to the northwest hav- 
ing been uplifted. In the bed of every stream crossing the 
fault, evidence of the fracture was found in the crushed and 
slickensided condition of the rocks, but the fault plane was 
nowhere exposed. Locally the rock has been so greatly sheared 
as to destroy all traces of the bedding planes. Very marked 
overthrown dips occur in a cut just west of Flagtown station, 
which increase in steepness towards the fracture. Folds in the 
Brunswick beds on the southeast side terminate abruptly against 
the fault and do not affect the beds on the opposite side. The 
high Sourland plateau composed of the hard trap and resistant 
The details of structure, which must be omitted here, are given in the Annual 
Report of the State Geologist of New Jersey for 1896, pp. 72-78. 
