THE NEWARK SYSTEM OF NEW JERSEY 553 
the calculation. More than this, the sweeping curve of these 
rocks, the uniform width of the belt, and the possibility of 
tracing certain subordinate but well-marked layers continuously 
along the strike, precludes the idea that any great part of its 
apparent thickness is due to repetition by faulting. Three 
independent measurements, made at intervals several miles 
apart gave results of 3540 feet, 3450 feet, and 3500 feet 
respectively. 
Three measurements of the thickness of these same beds in 
the Sourland plateau gave substantially the same results, z. é., 
3600 feet, 3650 feet, and 3660 feet. The fact that for a part of 
the distance a great trap sheet has been intruded into these 
beds and elsewhere has caused changes in the adjoining red 
shales, makes it a little more difficult to measure these beds. 
The fact that the thickness of these beds in Sourland plateau 
agrees so closely with that of the same beds on Hunterdon 
plateau is further reason for believing that the figures here given 
represent very closely the actual thickness. To suppose other- 
wise is to assume that these two separate areas are each trav- 
ersed by faults, whose throw, by a remarkable coincidence, is 
almost exactly the same, but no traces of which have been dis- 
covered by areal work of the most detailed character. 
The thickness of the Lockatong beds of the belt near Ewing- 
ville and Princeton seems to be only about half of that in the 
other two regions, z.¢., 1700 to 1800 feet. As noted above, the 
same relative thinness was observed in the Stockton beds near 
Trenton as compared with those further north. The explana- 
tion may lie in the fact that the beds of the thinner belts are 
nearer the old shore line than the others. Stratified deposits 
have the form of an unsymmetrical lens which thins out very 
rapidly shoreward and very gradually seaward. It is to be 
expected, therefore, that the thickness of this belt would be 
somewhat less than that of the others, but it may be fairly ques- 
tioned whether in the case of such fine deposits the difference 
would be so great as that indicated by the figures. 
The thickness of the Brunswick beds is even more difficult 
