38 



be no hesitation in referring the fossil leaves to the latter rather 

 than to the former. The leaflet of Cycas is distinguished by a 

 strong nervure which runs along the middle ; that of Zamia 



Eestoration of Zamia Gigas. 



has no such strong nervure along the middle, but a considerable 

 number of fine nervures, which proceed from the base of the 

 leaflet, then run parallel to one another, and terminate, not at 

 the apex, as is the case with most other plants, but along the 

 margin of the leaflet. This remarkable pecuharity may be ob- 

 served most distinctly in the leaflets of the fossil. Hence it was 

 referred to the genus Zamia ; and the species, found so abun- 

 dantly at Runswick, was called by M. Adolphe Brongniart, 

 Zamia Mantellii. He mentions it under this name, together 

 with makiy other species, in his Prodrome (Vune Histoire des 

 Vegetaux Fossiles, published in 1828. Almost coincidently Pro- 

 fessor Phillips employed for these plants the generic denomination 



