RKDORT ON tHE GEOLOGY OK NORTH AMERICA. 5/ 



ophytes and Echini, and a few species of shells. These fossils, 

 with a few exceptions, have also been found in the arenaceous 

 bed ; but many of the organic remains of the latter are not ob- 

 served in the limestone strata, which have not yielded any raul- 

 tilocular univalves, unless the doubtful fossil Belemnites} am- 

 biguiis be of this character : neither do they contain Terebra- 

 tulce nor Exogyrce." 



Throughout the marl region of New Jersey, the traces of 

 an extensive denudation of the former surface are everywhere 

 conspicuous ; and, what is remarkable, the excavation has ex- 

 tended almost invariably down to the marl stratum, but hardly 

 in any case through it; the consequence of which is, that nearly 

 all the meadows and low grounds, which are very numerous, 

 expose this deposit immediately beneath the surface. These 

 depressions in the surface are always occupied by creeks and 

 streams, many of them receiving the tide, while the rest are 

 only a few feet above it. The uplifting force must therefore 

 have operated very equally over the whole i-egion, as the strata 

 tliemselves sufficiently evince in their undisturbed features and 

 luiiformly horizontal position, wherever they are seen, from 

 Salem to their termination on the shores of Amboy Bay. The 

 Neversink Hills, Mount Holly, and Mullica Hill, are low insu- 

 lated outlying liills, from 100 to 200 feet elevation, having, 

 like all the ridges in this region, their longer axes parallel with 

 the Delaware river, or in other words, with the longitudinal 

 diameter of the tract. These hills and ridges are almost inva- 

 riablj'^ capped by a thin layer of the superficial ferruginous sand- 

 stone or conglomerate, which I have before stated to be the 

 general overlying rock of the marl deposits. The mineralogical 

 nature of this rock, its uniform parallelism to the other second- 

 ary beds wherever the surface has not sustained much denuda- 

 tion, its universal occurrence in scattered fragments throughout 

 all the intervening denuded tracts, and the quantity of the green 

 grains in it, are all reasons to induce me to think that this rock 

 is a true member, and the uppermost bed of the New Jersey 

 secondary group. The whole formation expands towards its 

 north-eastern extremity ; in approaching which it seems like- 

 wise to increase regularly in elevation, attaining its greatest 

 height in the Neversink Hills. As to the various upheaving 

 and denuding actions which have brought this portion of New 

 Jersey to its present configuration, I am not now prepared to 

 speculate, but shall merely in this place remark, that the valleys 

 adjoining the streams in this tract, like the valleys in the tertiary 

 districts further south, are never covered by the diluvium which 

 invests the general surface of the country. They are also of 



