DISTRIBUTION OF FOSSIL FERNS. 465 
mation of the Carboniferous strata of the Tran- 
sition Series. 
In strata of the Secondary Series, the absoUite 
and relative numbers of species of Ferns consi- 
derably diminishes, forming scarcely one third 
of the known Flora of these midway periods of 
geological history. (See PL 1. Figs. 37. 38. 39.) 
In the Tertiary Strata, Ferns appear to bear to 
other vegetables nearly the same proportion as in 
the temperate regions of the present Earth. 
or leaf stalks have fallen off. In Palms and other arborescent 
Monocotyledons, the leaves, or Petioles, embrace the stem and 
leave broad transverse scars, or rings, whose longer diameter is 
horizontal. In the case of Ferns alone, with the single excep- 
tion of Angiopteris, the scars are either elliptic or rhomboidal, 
and have their longer diameter vertical. 
M. Ad. Brongniart (Hist, des Veg. Foss. p. 261, PI. 79. 80.) 
has described and figured the leaf and stem of an arborescent 
fern (Anomopteris, Mougeottii) from the variegated sand-stone 
of Heilegenberg in the Vosges. Beautiful leaves of this species, 
with their capsules of fructification sometimes adhering to the 
pinnules, abound in the New red sand-stone formation of this 
district. 
M. Cotta has published an interesting Work on fossil Remains 
of arborescent ferns, which occur abundantly in the New red 
sand-stone of Saxony near Chemnitz. (Dendrolithen. Dresden 
and Leipsig, 1832.) These consist chiefly of sections of the 
Trunks of many extinct species, sufficiently allied in structure to 
that of existing arborescent Ferns, to leave little doubt that they 
are the remains of extinct species of arborescent Plants of this 
family, that grew in Europe at this Period of the Secondary for- 
mation. 
CiEOL. H II 
