FOSSIL PLANTS. 
403 
Pecopteris elegans, Germ. 
Pohjpodites elegam, Gopp., Syst., p. 344. 
PI. xv, fig. 10. 
We have in abundance, in the concretions of Mazon creek, specimens which 
agree in every point with the figures and description of this species. Pin- 
nffi, bearing linear leaflets, entire on the borders, round at the top, marked 
by medial nerves from which branch in an acute angle simple veins, ascending 
straight to the borders, or sometimes slightly curving upwards. But the 
characters here indicated are so variable and passing by such inappreciable 
transitions to those of the true Pecopteris unita , Brgt., that after the examina¬ 
tion of many hundred specimens, it is impossible to point out a single trait 
which could be described as distinctive of one of these species. I therefore 
consider this Pecopteris elegans , Germ., as a variety of Pecopteris unita , Brgt. 
''- V /jo 5 
Pecopteris aspidioides, Brgt., Veg. foss., p. 311. 
/ . 
PI. 112, fig 2. 
Found at Mazon creek; rare; seen only in two specimens. 
Pecopteris abbreviata, Brgt., Veg. foss., p. 337. ■ 
PI. 115, fig. 1 to 4. 
Numerous and very fine specimens in concretions from Mazon creek arc 
referable to this species, rather by the figures given of it by Geinitz in his 
Yersteinerimgen, than to those of Brongniart. The secondary pinme are short, 
all equal, the veins and veinlets much inflated, the pinnules more generally 
disconnected f. c. f. It is altogether a different species from Pecopteris Miltoni 
Brgt., to which the German author unites it as a variety, at least, if we con¬ 
sider our American specimens identical, which, however, may represent a new 
species. 
