PART II. 



GEOLOGY OF THE SOUTHERN DIVISION OF THE STATE. 



Introductory Remarks. 



The strata of the southern half of the State arrange themselves 

 in two distinct groups, and belong to two separate periods. The 

 oldest or earliest deposited of these groups is proved, by the 

 character of its organic remains, to have originated during the 

 latest eras of the secondary period, while the more modern belongs 

 to an earlier epoch of the succeeding tertiary dates. 



In tracing these deposits over any considerable area, ^^e disco- 

 ver that the whole series, though nearly horizontal, possesses an 

 appreciable dip towards the southeast. As a consequence of this 

 slight inclination, the lower strata rise successively to the surface 

 as we advance towards the northwest ; those at the bottom of 

 the series forming the northv;estern boundary of the region, where 

 they repose upon the more steeply dipping beds of the middle 

 secondary and primary formations, between Trenton and the 

 Raritan river. 



A gently undulating line, drawn from Shark Inlet on the 

 Atlantic coast, to Salem, separates the secondary and tertiary 

 groups. The district to the northwest of this line comprises only 

 the former, while that to the southeast contains the latter. The 

 tertiary region is extensively overspread, however, by a deep 

 covering of nearly white oceanic sand, destitute of organic 

 remains. We are thus precluded, not only from ascertaining 

 definitively to what precise date we ought to refer this super- 

 ficial stratum, but the extent to which it conceals the tertiary and 

 secondary deposits. The tracts in which the former are actually 

 exposed near the surface, are comparatively inconsiderable. 



