1 8 THE RARITAN FLORA. 



contemporaries of the huge and uncouth reptiha, the Dinosaurs, 

 Mososaurs, etc., which have long since vanished. 



In leading up to a consideration of the Raritan formation, 

 we need not go back farther than the close of the Triassic period. 

 After the deposition of these Triassic sandstones and shales 

 with their accompanying intrusions and extrusions of igneous 

 rock, the whole region was elevated (the post-Triassic uplift). 

 The rising land was immediately subjected to erosion, which 

 went on during the whole of the Jurassic and Lower Cretaceous 

 periods until at length the surface was essentially a vast plain, 

 the Sthooley peneplain, as it is called. At some time about 

 the close of the Lower Cretaceous there was a subsidence, or 

 warping, of this Schooley plain, and deposition along its eastern 

 flank succeeded erosion. What remains of these sediments now 

 constitute the Raritan formation of the Coastal Plain, its out- 

 crops forming the western border of the latter. Its strata, dip- 

 ping to the southeast, are successively overlain by younger sedi- 

 ments so that in wells, like that at Asbury Park, several hundred 

 feet of more recent materials are passed through before the 

 Raritan clays and sands are encountered by the driller. 



DESCRIPTION. 



The Raritan formation is made up for the most part of alter- 

 nating beds of clay and sand, with local lignitic deposits and 

 gravel. They vary greatly horizontally, as well as vertically, 

 SO' much SO' that the different members which are reasonably well 

 defined in Middlesex County cannot be traced with any degree of 

 assurance to the southwest. The clays are of various kinds, 

 ranging from arenaceous, pyritiferous, at times laminated and 

 ligiiitic clays, suitable only for the manufacture of common brick, 

 to almost white, massive, high-grade fire clays. All of the clay 

 beds are lenticular and some thin out and disappear in compara- 

 tively short distances. The sands are equally variable, some are 

 sharp, nearly pure quartz, others are highly micaceous or lig- 

 nitic or arkosic, and cross-bedding is frequently seen. The ma- 

 terials, as a whole, in both their character and rapid lateral 

 variation, are just such deposits as would probably be found 



