vel. The characters of the Cryptogam and Phanerogam are so mixed up
in it that, although the special lines of development are difficult to
trace, it is one massive testimony to the evolution of the higher
from the lower. The reproductive bodies of the great Lepidodendra are
sometimes more like seeds than spores, while both the wood and the
leaves of the Sigillaria have features which properly belong to the
Phanerogam. In another group (called the Sphenophyllales) the characters
of these giant Club-mosses are blended with the characters of the giant
Horsetails, and there is ground to think that the three groups have
descended from an earlier common ancestor.

Further, it is now believed that a large part of what were believed to
be Conifers, suddenly entering from the unknown, are not Conifers at
all, but Cordaites. The Cordaites is a very remarkable combination of
features that are otherwise scattered among the Cryptogams, Cycads, and
Conifers. On the other hand, a very large part of what the geologist had
hitherto called "Ferns" have turned out to be seed-bearing plants, half
Cycad and half Fern. Numbers of specimens of this interesting group--the
Cycadofilices (cycad-ferns) or Pteridosperms (seed-ferns)--have been
beautifully restored by our botanists. [*] They have afforded a new and
very plausible ancestor for the higher trees which come on the scene
toward the close of the Coal-forests, while their fern-like characters
dispose botanists to think that they and the Ferns may be traced to a
common ancestor. This earlier stage is lost in those primitive ages from
which not a single leaf has survived in the rocks. We can only say
that it is probable that the Mosses, Ferns, Lycopods, etc., arose
independently from the primitive level. But the higher and more
important development is now much clearer. The Coal-forest is not simply
a kingdom of Cryptogams. It is a world of aspiring and mingled types.
Let it be subjected to some searching test, some tremendous spell of
adversity, and we shall understand the emergence of the higher types out
of the luxuriant profusion and confusion of forms.

* See, especially, D. H. Scott, "Studies of Fossil Botany"
(2nd ed., 1908), and "The Evolution of Plants" (1910--small
popular manual).

CHAPTER IX. THE ANIMALS OF THE COAL-FOREST

We have next to see that when this period of searching adversity
comes--as it will in the next chapter--the animal world also offers a