I04 THE HISTORY OF CREATION. 



our hot-houses, can however give us hut a faint idea of 

 the stately and splendid frondose ferns of the primary 

 period, whose mighty trunks, densely crowded together, 

 then formed entii'e forests. These trunks, accumulated in 

 super-incumhent 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 

 branchiag veins or bunches of vessels in their tender foliage, 

 can still be as distinctly recognized in the impressions of the 

 palaeolithic 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 Calamarise, Ophioglossse, and Rhizocarpese seem to 

 have developed as three diverging branches out of the 

 Frondose Ferns, or Pteridee. The Calamarise, or Calamophyta, 

 have remained at the lowest level among these three classes. 

 The Calamariae comprise three different orders, of which 

 only one now exists, namely, the Horse-tails (EquisetaceEe). 

 The two other orders, the Giant Reeds (Calamitese), and the 

 Star-leaf Reeds (Asterophylliteae), are long since extinct. 

 All Calamarise 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 



