THE NEWARK ROCKS 45 



equally reliable. Six sections were made across the Lockatong 

 beds with the following results : Across the belt on the Hun- 

 terdon plateau, 3540 feet, 3450 feet, 3500 feet; across the 

 Sourland Mountain area, 3600 feet, 3650, 3660 feet. The 

 sweeping curve of this belt in the Hunterdon area, its uniform 

 width, and the possibility of tracing certain subordinate but 

 well-marked layers continuously along the strike preclude the 

 idea that any great part of its apparent thickness is due to 

 repetition by faulting. Furthermore, the fact that the beds on 

 the Sourland plateau agree in thickness so closely with the same 

 beds on the Hunterdon plateau is further reason for believing 

 that the figures here given represent very closely the actual 

 thickness. To suppose otherwise is to assume that these two 

 separate areas are each traversed by faults, whose throw, by a 

 remarkable coincidence, is almost exactly the same, but of which 

 no traces have been discovered by areal work of the most 

 detailed character. 



The thickness of the Lockatong beds, near Ewingville and 

 Princeton, seems to be only half of that in the other two regions, 

 i. c, 1700 to i8co feet. The same relative thinness was 

 observed in the Stockton beds, near Trenton, as compared with 

 those further north. The explanation of this may lie in the 

 fact that the beds of the former belt 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, which is nearest the old shore, would 

 be somewhat less than that of the others. The weight of evi- 

 dence indicates that in the deeper parts of the estuary the 

 Lockatong beds were 3500 or 3600 feet thick. 



The estimates for the Stockton and Brunswick beds are more 

 uncertain. In favor of the estimates given above these facts 

 may be urged. West of Ringoes the Brunswick shales form a 

 syncline whose axis plunges northwest. Between 6000 and 

 7000 feet of shales are involved in this fold. It is improbable 

 that a fault could follow the curving strike so as to repeat the 



