have taken place. What, then, has exterminated so many
species and whole genera? The mind at first is irresistibly
hurried into the belief of some great catastrophe; but thus
to destroy animals, both large and small, in Southern Patagonia,
in Brazil, on the Cordillera of Peru, in North America
up to Behring's Straits, we must shake the entire framework
of the globe. An examination, moreover, of the geology of
La Plata and Patagonia, leads to the belief that all the
features of the land result from slow and gradual changes. It
appears from the character of the fossils in Europe, Asia,
Australia, and in North and South America, that those conditions
which favour the life of the _larger_ quadrupeds were
lately co-extensive with the world: what those conditions
were, no one has yet even conjectured. It could hardly have
been a change of temperature, which at about the same time
destroyed the inhabitants of tropical, temperate, and arctic
latitudes on both sides of the globe. In North America we
positively know from Mr. Lyell, that the large quadrupeds
lived subsequently to that period, when boulders were
brought into latitudes at which icebergs now never arrive:
from conclusive but indirect reasons we may feel sure, that
in the southern hemisphere the Macrauchenia, also, lived
long subsequently to the ice-transporting boulder-period. Did
man, after his first inroad into South America, destroy, as
has been suggested, the unwieldy Megatherium and the
other Edentata? We must at least look to some other cause
for the destruction of the little tucutuco at Bahia Blanca, and
of the many fossil mice and other small quadrupeds in
Brazil. No one will imagine that a drought, even far severer
than those which cause such losses in the provinces of La