DESCRIPTION OF TIIK SPECIES. G7 



flora IS ill the Potomac terraue, the one which came next to the Potomac 

 flora amoiig its predecessors. 



Cladopiilki!IS Brong., ex parte. 



Saporta' iir.st dehiied the character of the genus Cladophlehis. He 

 gives the foUowiug description: "Frond piniiately divided; pinnules sep- 

 arate from one another, or shglitly united, attached to tlie racliis by the 

 entire base." Schimper' gives a much fuUor analysis of the generic char- 

 acter. He says: "Fronds pinnately divided ; pinna' spreading; lobes or 

 pinnules att;iched by the entire base, sometimes confluent, rarely slightly 

 auriculate, acuminate, or obtuse, occasionally dentate, especially at the 

 apex, not rarely subfalcately curved upwards ; midnerves pretty strong; 

 secondary nerves departing at a more or less acute angle, dichotomous 

 a little above the base, and repeatedly dichotomous : slender to very 

 slender." 



In his later work, however, for Zittel's Ilandbuch der Palaeontologie, 

 he makes no mention of this genus. If we modify Schimper's descrip- 

 tion so as to make it read, midnervo strong at base, and towards the sum- 

 mit dissolving into branches, we have a very accurate description of a 

 group of ferns that is strongly characteristic of the Jurassic, and which is 

 fully as much entitled to be called a genus as is Sphenoptcrls or Pccop- 

 ter'is. In my opinion it is necessar}'- to retain the name Cladophlchls for 

 all fossil plants with the above-described chai-acter, and which have no 

 fructification by which they can be placed in other genera. It does not 

 seem proper, as some have done, to group under this specific name all 

 the Jurassic plants of the Cladophlebis type, which have more or less 

 resemblance to the J'ccopfcris Whiibknsis of Lindley and Hutton and the 

 different plant given the same name by Brongniart. Pccoptcris Wklthicn- 

 slx, used by lleer as a specific name for plants widely diffused over the 

 world in the Jurassic i)eriod, is nearly ecpnvalent to the generic name 

 ChuhpMchis. Again, because certain Jurassic plants of the Cladophlfhis 

 ty[)e have in their foliage some of the features of ferns possessing the fruc- 

 tification of Aspleniiim, Dichsonia, etc., it does not seem proper to group 



' Pal. Franc, 2d aeries, Vogdtaux, PI. Jurass., vol. 1, pp. '293, -299. =Trait^tle Pal. V<Sg., vol. 3, p. 503. 



