FERNS. 
4(JI 
Pl'ical approximation to the Equator, is found 
the fossil species of this order to accompany 
tile higher degrees of Antiquity of the strata in 
"iiich they occur ; and this without respect to 
tile latitude, in wliich these formations may ho 
placed. M. Ad. Brongniart (Prodrome, p. 167) 
’^numerates twelve species of Calamites and two 
Equiseta in his list of plants found in strata 
the Carboniferous order. 
Ferns* 
The family of Ferns, both in the living and 
i'ossil Flora, is the most numerous of vascular 
t^ryptogamous plants.t Our knowledge of the 
geographical distribution of existing Ferns, as 
Connected with Temperature, enables us in some 
'iegree to appreciate the information to be de- 
^’i^ed from the character of fossil Ferns, in regard 
the early conditions and Climate of our globe. 
* See PI. I. No. 6. 7. 8. 37. 38. 39. 
+ Ferns are dislinguislied from all other vegetables by the 
P'^culiar division and distribution of the veins of the leaves ; and 
Arborescent species, by their cylindrical steins without branches. 
And by the regular disposition and shape of the scars left upon 
stem, at the point from which the Petioles, or leaf stalks, 
''Ave fallen off. Upon the former of these characters M. Ad. 
brongniart has chiefly founded bis classification of fossil Ferns, 
being impossible to apply to them the system adopted m the 
'‘'■'■angement of living Genera, founded on the varied disposition 
Althe fructification, which is rarely preserved in a fossil state. 
