FLORA AND THE AGE OF RARITAN FORMATION 253 



J. S. Newberry, in 1890, recognizing the Amboy Clays as Cenomanian 

 in age and synchronous with the Dakota Group of the West. Profes- 

 sor Lester F. Ward was the first to point out that the Raritan was 

 older than the Dakota Group, which is undoubtedly the case, and it 

 has been customary in recent years to follow the latter author and 

 regard the former as roughly corresponding to the Gault of England 

 and the Albian of continental Europe. The view here presented is 

 that the Raritan flora is much more closely allied with the Cenomanian 

 of the Old World than it is with the Albian or Gault. At the same 

 time it is quite obviously older than the Magothy flora, that of the 

 Dakota Group, and those of the South Atlantic Coastal Plain,' so that 

 if these latter are to be considered of Cenomanian age they are to be 

 regarded as Upper Cenomanian while the Raritan is to be regarded 

 as Lower Cenomanian. European geology furnishes a similar case 

 in the division of the Cenomanian into the substages Rotomagian and 

 Caretonian, although probably the parallelism of substages cannot 

 be carried across the ocean. European paleontology furnishes 

 abundant and well-characterized Cenomanian and Senonian floras 

 for comparison and by this standard the Raritan as well as the some- 

 what younger Dakota and Magothy floras are clearly Cenomanian 

 floras. The Turonian stage of European geology on the other hand 

 has thus far yielded so meager a flora that it is practically useless as 

 a basis for comparison and it may well be that the flora of the Dakota 

 Group along with its southern and eastern representatives — the 

 Woodbine, Tuscaloosa, Eutaw, Black Creek, Middendorf, and 

 Magothy floras — represents the Turonian stage of Europe. Strati- 

 graphically there is no contrary evidence and the Dakota sandstone 

 would simple go with the overlying Benton which invertebrate 

 paleontologists have long considered as representing the Turonian. 



The paleobotanical evidence for the Cenomanian age of the Raritan 

 formation is briefly as follows. On general grounds we find the 

 Raritan flora more complex and modern in its composition than any 

 known Albian flora; for example, dicotyledons make up 68 per cent, 

 of the Raritan flora while not a single dicotyledon is known from the 

 English Gault and the representation of this group of plants in the 



I Older Cretaceous deposits are known from North Carolina to Alabama, but 

 these are, so far as known, unfossiliferous. 



