10 



bottom of the group, will be found to encircle very extensively 

 the bottom of the hills, or spurs of the Highlands, and to repose 

 at a m'oderate inclination unconformahly upon the primary rocks 

 of which these hills are composed. In like manner, both along 

 the southeastern foot of the Highlands and around the Green 

 Pond Mountain, the rocks of the middle secondary group are 

 seen to overlie these lower secondary or Appalachian rocks with 

 an unconformable inclination, which plainly establishes the sub- 

 sequence of their date, by showing that the others had already 

 been uplifted before these overlapping rocks were deposited upon 

 them. We behold the trap rocks resting in many instances in 

 their turn upon the middle secondary strata of their district, 

 and with such obvious appearances at the line of contact of the 

 two formations of a disruption and partial fusion of the latter, as 

 to leave no doubt in the mind of the observer, that the former 

 were poured out through fissures in the middle secondary rocks, 

 at a period when these had been already deposited, and at least 

 partially solidified. 



The following tabular arrangement of the rocks and strata of 

 the northern division of the State, specifies the name and nature 

 of the several formations, and exhibits the order of their succes- 

 sion from the trap, which is the newest rock of the region, to the 

 primary strata, which are the oldest. 



The Geological Map will render intelligible the range and ex- 

 tent of each of these formations, while the accompanying S'ec</o?zs 

 will point out the manner in which they are_ severally related in 

 the order of superposition. 



TABLE, 



Shmoing the order of succession of the rods forming the northern 

 division of JVew Jersey. 



Trap Rocks. — Generally coarsely crystalline; sometimes fine- 

 grained and basaltic ; they rest unconformahly upon the 

 middle secondary strata, through which they have been pro- 

 truded. 



Middle Secondary Rocks. 



1. Variegated calcareous conglomerate. Generally a very 

 heterogeneous rock, in which a large proportion of the 



