178 THE rOTOxMAC OK YOUNGEK MESOZOIG FLORA. 



given b}' Zig-no. It has the same mode of insertion of the nerves, which 

 are irregular, forking, and anastomosing, but in Cfciils falcata the leaflets 

 are decurrent, and become much widened at their insertions. The Potomac 

 plant is more like Nathorst's plant from the Rhaitic of Sweden, which he 

 iirst named Anthrophyopsis Nilssoni, and afterwards called Ctems faUax 

 The termination, especially of the leaflets in the two plants, shows a resem- 

 blance. PI. CXXXVIII, Fig. 12, gives what seems to be the middle of a 

 leaf of large size. Fig. 11 gives the upper portion of a leaf that seems to 

 have been much larger than that depicted in Fig. 12, as is shown in the 

 much greater width of the midrib. This specimen is a good deal distorted 

 by pressure, so that its true character may be disguised. The wide midrib 

 seems to be split into two branches, which are connected by smaller nerves. 

 The fragment of a leaflet visible on its left-hand side seems to have had its 

 base pressed over upon the upper surface of the midrib, while the lower 

 half of that on the right hand seems to have been torn away by the 

 splitting off and detaching of a portion of the midrib. The specimen 

 given in Fig. 10 seems to be the tip of a leaflet, perhaps corresponding to 

 the basal jjortions shown in Fig. 12. 



PODOZAMITES Fr. Braun (emend.). 



Leaves small, with a slender rachis, pinnate ; leaflets alternate, remote, 

 directed more or less upward, with a gradually narrowed base, often fur- 

 nished with a short petiole, ovate-elliptical, elongate, lancet-shaped, or 

 linear, sometimes somewhat curved, detaching themselves from the rachis, 

 and usualh^ found isolated ; nerves forked at the base, often very fine and 

 closely placed, parallel with the margin to near the tips of the leaflets, 

 where they converge. 



The genus Podozamites is represented in the Potomac flora apparently 

 by a considerable number of species ; but as the specimens appear usually 

 in the form of fragmentary and detached leaves, they do not generally 

 admit of a full characterization and positive determination. The leaflets 

 having the character of PoJozamiies are quite rare, and the genus con- 

 tributes no important element to the flora. They give one the impression 

 i)f a type in decadence Most of them are in form strikii^gly like the 



