30 H. B. KUMMEL 



the Raritan River. They do not, however, appear in the region 

 west of the Palisades and north of Newark (Fig. 3). In the 

 region in which they would be expected to occur the broad 

 Newark and Hackensack meadows are found. The Lockatongf 

 beds are always ridge makers, rising above the level of the rocks 

 on either side, and therefore it is impossible to suppose that they 

 underlie these great tide-water meadows. There can be no 

 doubt but that the argillites do not exist in the northern region. 

 It is hardly probable that sedimentation ceased entirely in this 

 northern area while the argillites were being deposited in the 

 southwest, since there is no evidence of such oscillations of sea 

 level or of unconformity. It seems more probable that the con- 

 ditions favoring their formation did not prevail in the northern 

 part of the basin ; that here the red shales and sandstones were 

 deposited contemporaneously with the argillites and flagstones- 

 to the southwest, and that, could we trace the latter from the 

 point near Princeton, where they disappear beneath the Pen- 

 sauken and Cretaceous deposits, we would find all the steps in 

 their transition to the soft red shales. 



The Brunswick beds likewise change in texture towards the 

 northeast. They are predominantly soft argillaceous shales 

 from the Delaware River as far as Elizabeth. In some layers 

 an increase in coarseness is noticeable, which continues north- 

 eastward along the strike, until in the vicinity of Newark and 

 Orange the beds are chiefly sandstones. Many of these beds 

 resemble the brownstones of the Stockton series, so closely 

 in fact that hand specimens can be distinguished with difficulty, 

 if at all, from much of the sandstone at Trenton and Stockton. 

 But their stratigraphical position in the Newark series seems 

 to be far above that of the Stockton beds. The facts on 

 which this conclusion is based are as follows. The trap sheet 

 forming First Mountain is extrusive in origin. That is, it is an 

 overflow sheet, 1 and, therefore, its base is conformable to the 



1 This might not be the case had the lava flowed over an eroded land surface, but 

 evidence will be given below to prove that the lava flow was subaqueous, and there- 

 fore contemporaneous with the deposition of the adjoining shales. Its base therefore 

 represents a constant horizon. 



