As we turn over the pages
of the geological chronicle, an extraordinary change comes over
the vegetation of the earth. The great Lepidodendra gradually
disappear before the close of the Permian period; the Sigillariae
dwindle into a meagre and expiring race; the giant Horsetails
(Calamites) shrink, and betray the adverse conditions in their
thin, impoverished leaves. New, stunted, hardy trees make their
appearance: the Walchia, a tree something like the low Araucarian
conifers in the texture of its wood, and the Voltzia, the reputed
ancestor of the cypresses. Their narrow, stunted leaves suggest
to the imagination the struggle of a handful of pines on a bleak
hill-side. The rich fern-population is laid waste. The seed-ferns
die out, and a new and hardy type of fern, with compact leaves,
the Glossopteris, spreads victoriously over the globe; from
Australia it travels northward to Russia, which it reaches in the
early Permian, and westward, across the southern continent, to
South America. A profoundly destructive influence has fallen on
the earth, and converted its rich green forests, in which the
mighty Club-mosses had reared their crowns above a sea of waving
ferns, into severe and poverty-stricken deserts.
Pages:
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228