The More I Reflect On This
Case, The More Interesting It Appears:
I know of no other
instance where we can almost mark the period and manner
of the splitting up of one great region into two well-
characterized zoological provinces.
The geologist, who is fully
impressed with the vast oscillations of level which have
affected the earth's crust within late periods, will not fear
to speculate on the recent elevation of the Mexican platform,
or, more probably, on the recent submergence of land
in the West Indian Archipelago, as the cause of the present
zoological separation of North and South America. The
South American character of the West Indian mammals [6]
seems to indicate that this archipelago was formerly united
to the southern continent, and that it has subsequently been
an area of subsidence.
When America, and especially North America, possessed
its elephants, mastodons, horse, and hollow-horned ruminants,
it was much more closely related in its zoological
characters to the temperate parts of Europe and Asia than
it now is. As the remains of these genera are found on
both sides of Behring's Straits [7] and on the plains of
Siberia, we are led to look to the north-western side of North
America as the former point of communication between the Old
and so-called New World. And as so many species, both
living and extinct, of these same genera inhabit and have
inhabited the Old World, it seems most probable that the
North American elephants, mastodons, horse, and hollow-
horned ruminants migrated, on land since submerged near
Behring's Straits, from Siberia into North America, and
thence, on land since submerged in the West Indies, into
South America, where for a time they mingled with the
forms characteristic of that southern continent, and have
since become extinct.
While travelling through the country, I received several
vivid descriptions of the effects of a late great drought; and
the account of this may throw some light on the cases where
vast numbers of animals of all kinds have been embedded
together. The period included between the years 1827 and
1830 is called the "gran seco," or the great drought. During
this time so little rain fell, that the vegetation, even to the
thistles, failed; the brooks were dried up, and the whole
country assumed the appearance of a dusty high road. This
was especially the case in the northern part of the province
of Buenos Ayres and the southern part of St. Fe. Very
great numbers of birds, wild animals, cattle, and horses
perished from the want of food and water. A man told me
that the deer [8] used to come into his courtyard to the well,
which he had been obliged to dig to supply his own family
with water; and that the partridges had hardly strength to
fly away when pursued. The lowest estimation of the loss
of cattle in the province of Buenos Ayres alone, was taken
at one million head. A proprietor at San Pedro had previously
to these years 20,000 cattle; at the end not one remained.
San Pedro is situated in the middle of the finest
country; and even now abounds again with animals; yet
during the latter part of the "gran seco," live cattle were
brought in vessels for the consumption of the inhabitants.
The animals roamed from their estancias, and, wandering
far southward, were mingled together in such multitudes,
that a government commission was sent from Buenos Ayres
to settle the disputes of the owners.
Enter page number
PreviousNext
Page 105 of 402
Words from 53717 to 54302
of 208183
