554 HENRY B. KUMMEL 
to estimate accurately. This is due to the uniformity of the red 
shale, which renders it very difficult to detect the presence of 
faults, to the folded structure, and to the fact that the entire 
thickness is not present in this part of the state. 
West of Ringoes the shales form a syncline whose axis 
plunges northwest. Estimates made here show that between 
7000 and 8000 feet of shales are involved in this folding. 
Between the mouth of Lawrence Brook, east of New Brunswick, 
where the shales disappear beneath the Cretaceous cover, and 
the base of First mountain, back of Bound Brook, the beds are 
10,000 feet thick, provided there are no faults in the interven- 
ing region. Inthe Raritan River bluffs below New Brunswick 
three fault breccias were found, but nothing is known as to 
the amount of dislocation beyond the fact that it was not suffi- 
cient to expose the Lockatong beds which are here at a horizon 
about 1000 feet lower. From the amount of disturbance and 
crushing which is known to accompany great faults in other 
parts of this area, the presumption is that these are Staal lan 
deduction of 1000 feet from the above estimate would seem to 
be ample for these and any undiscovered fractures. Nine thou- 
sand feet, however, is not enough, since neither the base nor the 
top of the Brunswick beds is included in this section. They 
certainly extend for 2000 to 3000 feet above the base of First 
Mountain. In the light of the present facts an estimated thick- 
ness of 12000 feet for the Brunswick shales does not appear 
excessive, although in view of the uncertainties connected with 
the structure, too much emphasis must not be placed upon it. 
The total thickness, therefore, of the sedimentary rocks of 
the Newark system in western New Jersey seems to be about 
20,000 feet. These figures are so great that one naturally hesi- 
tates to accept them, but the facts, so far as known, do not per- 
mit any other interpretation. I began my work feeling confident 
that the thickness of the beds was much less than this, and that 
they were many times repeated by faults. However, many of 
the faults found cross the beds at such angles as to be ineffec- 
tive in repeating the strata. Furthermore, the fact that the 
