GENERAL REMARKS. 125 



beds almost no conifers, but few cycads, and an immense number of indi- 

 viduals of one species of Equisetum, with quite a large number of species 

 of ferns. These important differences in the conditions of preservation, 

 without doubt, lessened the number of identical species in the two States, 

 which number was, no doubt, much greater than it appears to be from the 

 number of preserved species. 



It will be noted that I have placed in the Triassic column no species, 

 although the age of both the North Carolina and Virginia Mesozoic is held 

 by many to be Triassic, largely on the evidence of the plants. It will be 

 necessary, then, carefully to examine whether or not there is any such evi- 

 dence of Triassic age. 



On examining the list of names employed by Emmons, we meet with 

 several which if correctly determined would indicate a Triassic or Permian 

 age for the Mesozoic beds. The plants of this kind are the following: Cal- 

 amites arenaceus, the several Walchias, Pterozamites decussatus, Albertia lati- 

 folia, Nceggerathia striata. Professor Heer, in some notes on Emmons's 

 plants, published in the "American Journal of Science and Arts," November, 

 1857, considers Pecopteris bullata (Mertensides bullatus of this memoir) to be 

 nearly allied to Pecopteris Stuttgartensis {Lepidopteris Stuttgartensis of Schim- 

 per) from the Trias of Europe. I have included in the above list Emmons's 

 Pterozamites decussatus, because Professor Heer expressed the opinion that 

 it might be PterophyUum longifolium of the European Trias. 



The Catamites arenaceus of the above list is merely the internal cast of 

 Equisetum Rogersi, which is nearer Equisetum columnare than any other 

 foreign plant. Even were it more closely allied to Equisetum arenaceum, this 

 would not compel us to place it wholly among Triassic plants, for Saporta 

 has shown, in "Pal. Francaise," "Plantes jurass.," that this Equisetum goes up 

 into the base of the Rhsetic in France. Pterozamites decussatus, or PterophyUum 

 decussation, is more nearly allied to PterophyUum Andrceanum, Schimp;, from 

 the Lias of Sweden, than to any other plant. The Nceggerathia and the 

 Walchias would indicate a Permian, and not a Triassic age. As to the 

 Permian age of the beds, no one will maintain it now. The Nceggerathia is 

 the basal portion of Baiera multifida, a plant perhaps without very near 

 affinities with any previously described ones, but which is nearer to Baiera 



