196 J. V. LEWIS NEWARK TRAP ROCKS OF NEW JERSEY 



(2) That there was further local depression, with corresponding 

 thickening of sediments, in the interval between the Second Mountain 

 flows and that of Long hill. 



(3) The crescentic trap ridge of New Vernon is definitely correlated 

 with that of Long hill. 



(4) The small extrusive remnants at Sand Brook and New German- 

 town are regarded as probably identical, or at least contemporaneous, 

 with the First and Second Mountain sheets. 



(5) The hypothesis of a feeding dike along the western flank of the 

 Palisades is regarded as highly improbable. 



(6) The continuity of the Palisades sill with the Eocky Hill trap, sug- 

 gested by several former observers, is practically established by data from 

 deep wells and dredging operations. 



(7) The further extension of the same sill to include Pennington and 

 Baldpate mountains, Sourland mountain, mount Gilboa, and the Byram 

 mass is regarded as almost equally certain. 



(8) Numerous dikes and other small masses are regarded as offshoots 

 of the Palisades sill. 



(9) The intrusives are regarded as of later origin than the extru- 

 sives and earlier than the deformation of strata by faulting and tilting. 



Introduction 

 area of the newark system 



Of the long sinuous belt of Newark rocks extending from southern 

 New York across New Jersey, Pennsylvania, Maryland, and into northern 

 Yirginia, perhaps a little more than one-fourth lies within the state of 

 New Jersey (see map, plate 1). It occupies about one-sixth of the total 

 area of the state in the form of a tapering belt from the Delaware river 

 above Trenton northeastward to the Hudson river and the New York 

 state boundary. On the Delaware it is 32 miles wide, and it narrows to 

 about 16 miles across where it passes into southern New York, including 

 wholly or in part the counties of Hunterdon, Mercer, Somerset, Middle- 

 sex, Union, Morris, Essex, Hudson, Passaic, and Bergen. 



TOPOGRAPHY 



. The Newark area comprises a Piedmont plain which is intermediate in 

 elevation and surface characters between the low, smooth Coastal plain to 

 the southeast and the higher and more mountainous Highlands on the 

 northwest. Along the northwestern border it is distinctly lower than the 

 adjoining Highlands except west of Flemington, where the elevation of 

 Hunterdon plateau approaches that of Musconetcong mountain. Along 

 the southeastern margin it gradually passes into the low Coastal plain. 



