FERNS. 4(31 
pineal approximation to the Equator, is found 
in the fossil species of this order to accompany 
the higher degrees of Antiquity of the strata in 
which they occur ; and this without respect to 
the latitude, in which these formations may be 
placed. M. Ad. Brongniart (Prodrome, p. 167) 
enumerates twelve species of Calaynites and two 
of Equiseta in his list of plants found in strata 
of the Carboniferous order. 
Ferns. * 
The family of Ferns, both in the living and 
fossil Flora, is the most numerous of vascular 
Cryptogamous plants, t Our knowledge of the 
geographical distribution of existing Ferns, as 
connected with Temperature, enables us in some 
degree to appreciate the information to be de- 
rived from the character of fossil Ferns, in regard 
to the early conditions and Climate of our globe. 
* See PL 1. No. 6. 7. 8. 37. 38. 39. 
f Ferns are distinguished from all other vegetables by the 
peculiar division and distribution of the veins of the leaves ; and 
in arborescent species, by their cylindrical stems without branches, 
and by the regular disposition and shape of the scars left upon 
the stem, at the point from which the Petioles, or leaf stalks, 
have fallen off. Upon the former of these characters M. Ad. 
Brongniart has chiefly founded his classification of fossil Ferns, 
it being impossible to apply to them the system adopted in the 
arrangement of living Genera, founded on the varied disposition 
of the fructification, which is rarely preserved in a fossil state. 
