I04 THE HISTORY OF CREATION, 
~ our hot-houses, can however give us but a faint idea of 
the stately and splendid frondose ferns of the primary 
period, whose mighty trunks, densely crowded together, 
then formed entire forests. These trunks, accumulated in 
super-incumbent masses, are found in the coal seams of the 
Carboniferous period, and between them, in an excellent | 
state of preservation, are found the impressions of the 
elegant fan-shaped leaves, crowning the top of the trunk in 
an umbrella-like bush. The varied outlines and the feather- 
like forms of these fronds, the elegant shape of the 
branching veins or bunches of vessels in their tender foliage, 
can still be as distinctly recognized in the impressions of the 
palzeolithic fronds as in the fronds of ferns of the present 
day. In many cases even the clusters of fruit, which are 
distributed on the lower surface of the fronds, are distinctly 
preserved. After the carboniferous period, the predominance 
of frondose ferns diminished, and towards the end of the 
secondary period they played almost as subordinate a part 
as they do at the present time. 
The Calamarize, Ophioglossee, and Rhizocarpeze seem to 
have developed as three diverging branches out of the 
Frondose Ferns, or Pteridee. The Calamari, or Calamophyta, 
have remained at the lowest level among these three classes. 
The Calamariz comprise three different orders, of which 
only one now exists, namely, the Horse-tails (Equisetacez). 
The two other orders, the Giant Reeds (Calamiteze), and the 
Star-leaf Reeds (Asterophylliteze), are long since extinct. 
All Calamarize are characterized by a hollow and jointed 
stalk, stem, or trunk, upon which the branches and leaves 
(in cases where they exist) are set so as to encircle the 
| jointed stem in whorls. The hollow joints of the stalk are 
