96 THE OLDER MESOZOIC FLORA OP VIRGINIA. 



them, or 28 per cent. The Rhsetic can, then, claim the largest percentage 

 of identical and allied species. Among these we find some of the most 

 abundant and characteristic forms of the Virginia flora. The great abun- 

 dance and wide diffusion of Macrotceniopteris maynifolia and Ctenophyllum 

 Braunianum give these plants especial weight. Acrostichides linncecefolius is 

 very characteristic of the Virginia Mesozoic, and it finds its near relative in 

 A. Gceppertianus, a plant highly characteristic of the Rhsetic. 



It is clear, then, from these facts that we must consider this flora as 

 not older than Rhsetic. The only question is whether or not its strong 

 Jurassic features ought to cause us to regard it as at least Lower Liassic 

 in age. I think that it is fully as much entitled to be regarded as of Liassic 

 age as is the flora of the Rajmahal Group of India. Feistmantel and 

 Zigno think that the age of this group is that of the Lias. 



Taking everything into consideration, the flora of the older Mesozoic 

 of Virginia is, of the European floras, nearest to that of Theta, near Bay- 

 reuth, in Franconia. It has elements which ally it with the plants found 

 by Dr. Newberry at Los Bronces, Sonora, and it is also allied to the flora 

 of Steierdorf, Banat, and to that of the Rajmahal Group in India, as well as 

 that of Bjuf in Sweden. As we shall see, it is essentially the same with the 

 flora of the Mesozoic strata of North Carolina, described by Dr. Emmons 

 in his "American Geology," Part VI. 



I append to the description of the flora of the Virginia Mesozoic a brief 

 account of that of North Carolina. For the sake of greater clearness I think 

 it best to give this under a distinct head, and to give in the plates copies of 

 Emmons's figures. 



