196 GEOIvOGICAL SURVEY OF NEW JERSEY. 



now find the northern edge of the clay belt to be, extending 

 from Woodbridge to Trenton. This was evidently a period of 

 quietude and slow subsidence, as the deposits indicate, during 

 which immense quantities of land vegetation were entombed, 

 many of the specimens so delicate that it is difficult to under- 

 stand how they could have been preserved, affording additional 

 evidence of the quiet conditions which must have prevailed. 

 This flora has been described by Dr. Newberry,* who recognized 

 in it 156 species, of which all but about 30 are angiosperms, 

 nearly all of them included under living genera. 



Many of these are genera which now inhabit the region, such 

 as Diospyros^ Juglans^ Liriodendron^ Magnolia^ Popuhis, &c., 

 but others are of foreign or more southern indigenous distribu- 

 tion, such as Bauhinia^ Cimtamomum, Eucalyptus, Ficus, Lau- 

 rus, Passiflora, Sequoia, &c. 



No living species is recognized, although close specific relation- 

 ship is indicated in one of the names adopted {Magnolia glau- 

 coides) and is commented upon in regard to others. The most 

 significant feature as a whole is the complete reversal of the pro- 

 portions between the angiosperms and gymnosperms when com- 

 pared with these proportions in the preceding formation, the 

 angiosperms being now overwhelmingly in the ascendant. The 

 genera also indicate a climate less tropical than that which 

 preceded it. 



After the clays had been laid down, as estuary or brackish 

 water deposits, as indicated by the occurrence of marine molluscs 

 in limited numbers, the submergence continued, and we next 

 find" the clay marls, representing a transition to marine condi- 

 tions. In these, as might be expected, the remains of land 

 vegetation are less abundant, but apparently the flora was not 

 noticeably different in its generic characters from that of the 

 clays, although a number of new species may be noted, f 



The subsidence continued and true marine conditions super- 

 vened. The marls were deposited and in them nothing but 

 marine organisms are preserved. Thus far we have not found 

 any record of the land vegetation which occupied the region 



* " The Flora of the Amboy Clays." Monographs of the U. S. Geol. Survey, Vol. XXVI. 



t See "The Cretaceous Clay Marl Exposure at Cliffwood, N. J." Arthur Hollick. Trans. N Y 

 Acad. Sci. Vol. XXI, p. 114. 



