Ancient Vegetation of the Earth. 317 
phenomena, which have necessarily required so many centuries 
for their accomplishment, were prior, in point of time, to the ere- 
ation of man. It conducts us alike to appreciate events, and to 
re-construct beings which have preceded, many thousand years, 
hot only the most ancient historical traditions, but also the very 
existence of our race. 
This prolonged history of the formation of the superficial strata 
of the earth, is constituted, like the history of nations, of periods 
of repose, or of tranquility sufficiently great, at least, for the 
waters and the dry land of the surface to become peopled by a 
variety of inhabitants ; and of periods of revolution, during which 
resistless forces have agitated this surface, elevating mountains, 
submerging lands previously dry, and causing ancient beds of 
oceans to issue from the bosom of the deep; in short, pouring 
over pre-existing rocks the materials for new layers which, envel- 
oping the ruins of living beings, destroyed by these violent con- 
vulsions, have thus preserved their remains as precious monu- 
ments which now reveal to us, after so many thousand years, the 
nature of the ancient inhabitants of our globe, and the order in 
which the several races of beings have succeeded each other. 
The study of the periods of these revolutions, and of those of 
repose, are alike of the most vivid interest: but the first are en- 
tirely the province of the geologist; while the second, on the 
contrary, necessarily require the light of the zodlogist or the bot- 
‘anist ; for these alone are able, by an exact comparison of the fos- 
sil remains of former beings with the corresponding parts of such 
as are now existent, to determine the relations which exist be- 
tween the inhabitants of the globe, at various and distant epochs. 
It was thus Cuvier, in his admirable researches upon fossil bones, 
basing his investigations upon the positive data which comparative 
anatomy furnishes, was enabled to re-construct the skeletons of 
the greater part of the animals of which the remains had then 
been discovered, and also to determine, with the greatest proba- 
bility, their exteriour forms, and their analogy to those animals 
with which we are now acquainted. 
Botany, notwithstanding it has long furnished fewer documents 
upon the ancient state of the globe, ought, nevertheless, to be 
equally laid under contribution, by the geologist ; and it is even 
able to cast more light than zoélogy upon the state of the terres- 
trial surface, during the most ancient periods of its formation, 
