Nov., 1890. 
PLANT MARCHES. 
251 
Although the abundant vegetation of the Carboniferous 
period is well represented at the present time in the Crypto- 
gamic plants already referred to, and the Pines and other 
trees of Mesozoic ages are in good evidence, it is in the much 
later deposits of the Cretaceous period that we must seek for 
the ancestors of many of the more advanced forms of 
vegetable life which at present adorn our woodlands, among 
which may be reckoned finely developed types of the Poplar, 
Oak, many kinds of Salix (Willow), Juglans (Walnut), Alder, 
Magnolias, Beech, Chestnut, Platanus, Tulip Trees (Lirio- 
dendron), &c. 
The abrupt extinctions of the flora at the terminations of 
geological epochs already referred to, are followed by the re¬ 
markable circumstance of the equally sudden appearance in 
the succeeding periods of apparently new vegetable creations. 
There are eminent botanists living who decline to accept 
the view that these new types are the modified or changed 
forms of still more remote ancestors, whose intermediate 
characters are untraceable owing to some hiatus in the records 
of the world’s history, and who express a preference to wait 
for some new revelation of science, which may throw more 
light upon the creation of complex organisms. Whilst I 
believe we have only to await further research for connecting 
types, I make reference to these opinions for the sake of calling 
attention to the fact that evolution, in its strictest sense, is 
not accepted by all botanists. 
I have already remarked that the submergence of land at 
the close of geological epochs—the Carboniferous period for 
instance—was a ready cause of the extinction of existing 
plant life, and after such a wave of destruction there would be 
but scant remains of the magnificent vegetation of the pre¬ 
ceding period. Upon the re-appearance of the land in a later 
age, plant life again spread over the world, but entirely from 
new centres, and it is remarkable that although the influence 
of the destructive forces has frequently, in the world’s history, 
driven the whole vegetable world from north to south, and 
the cessation of such adverse influences has again permitted 
its return—always however impoverished through its travels 
—yet all available data indicate that new and vigorous types 
of plant life have all proceeded from northern centres. 
Many interesting facts present themselves in connection 
with these Marches of Plants. Hardy plants from the north, 
either from compulsion or natural inclination, made successful 
war against vegetable occupants already in possession, and as 
they advanced southwards, and for the most part improved 
in size and beauty, they destroyed theirmore feeble opponents. 
