2CG 0. Feistmantel 



They are found mostly at only one locality, and by their occurrence 

 there, impart a newer aspect to the flora of that point. They, hence, 

 do not play any important part in the flora of the Potomac and 

 suggest the idea that they are new comers, not yet well established. 



The samé rarity and restriction in distribution is found in the 

 new genera Quercipkyllum, Popidopkyllum, Aceriphyllum, Aristolochiae- 

 phyllum, Hederaephyllum^ Eucalyptophyllum. They with Menispermites 

 occur almost entirely where the older elements are sparingly repre- 

 sented. They are so rarely found, and the specimens, when occur- 

 ring, are so scarce that these forms cannot be regarded as characte- 

 ristic and developed elements in the Potomac flora. Most of them 

 excepting Menispermites, are rather vaguely defined and comprehens- 

 ivel types. They are named from the living genera that they most 

 resemble. The complexity of type is strikingly shown in Araliaephyllum. 

 One of the species of Hederaephyllum, showing only two or three 

 specimens, has a leaf of very peculiar form whose entire outline 

 is formed of nearly straight lineš meeting under large angles. 



Aceriphyllwm is found only at one locality and in three or four 

 specimens at most. The single species has a remarkable leaf which shows 

 some of the features of Acer, Aralia and Liriodendron all combined. 

 These examples may suffice to give some idea of these rare genera. 

 The genera named next are more important on account either of 

 the greater abundance of specimens, or of their wider diffusion. 



Fícophyllum — This is a widely diífused genus, although nevěr 

 very abundant. It occurs mostly where the older Jurassic types pre- 

 dominate. The leaves háve mostly thick midribs, slender primary 

 nerveš, and a coarse irregular ultimate areolation. Fragments of le- 

 aves of one species of this genus, were the first of the fossils resem- 

 bling dicotyledons that were found, but the nervation was so like 

 that of some ferns that it was not until better specimens were found, 

 that the dicotyledonous nature could be certainly made out. 



Sapindopsis. — Most of the species of this genus occur in 

 company with the more recent looking plants of the Potomac flora 

 and at one locality leaves of one species are very numerous. The 

 leaves of this species, although much like those of Sapindus, show 

 in the uppermost pair and terminál leaflet remarkable variations. 

 Celastrophyllum and Saliciphyllum are not found where the older 

 types are abundant. The former is rather abundant at one locality. 

 Vitiphyllum. — Includes forms near fossils hitherto described as Cis- 

 sites but the incising of the leaves and toothing are more complex. 



