1843. ] RIO TERCERO. 127 
broken masses, covered with cacti and mimosa-trees. The real 
grandeur, however, of an immense river like this, is derived 
from reflecting how important a means of communication and 
commerce it forms between one nation and another; to whata 
distance it travels ; and from how vast a territory it drains the 
vgreat body of fresh water which flows past your feet. 
For many leagues north and south of San Nicolas and Roza- 
rio, the country is really level. Scarcely anything which travel- 
lers have written about its extreme flatness, can be considered as 
exaggeration. Yet I could never find a spot where, by slowly 
turning round, objects were not seen at greater distances in some 
directions than in others; and this manifestly proves inequality 
in the plain. At sea, a person’s eye being six feet above the 
surface of the water, his horizon is two miles and four-fifths dis- 
tant. In like manner, the more level the plain, the more nearly 
does the horizon approach within these narrow limits; and this, 
in my opinion, entirely destroys that grandeur which one would 
have imagined that a vast level plain would have possessed. 
October 1st.—We started by moonlight and arrived at the 
Rio Tercero by sunrise. This river is also called the Saladillo, 
and it deserves the name, for the water is brackish. I stayed 
here the greater part of the day, searching for fossil bones. 
Besides a perfect tooth of the ‘Toxodon, and many scattered 
bones, I found two immense skeletons near each other, projecting 
in bold relief from the perpendicular cliff of the Parana. They 
were, however, so completely decayed, that I could only bring 
away small fragments of one of the great molar teeth; but these 
are sufficient to show that the remains belonged to a Mastodon, 
probably to the same species with that, which formerly must have 
inhabited the Cordillera in Upper Peru in such great numbers. 
The men who took me in the canoe, said they had long known 
of these skeletons, and had often wondered how they had got 
there: the necessity of a theory being felt, they came to the 
conclusion that, like the bizcacha, the mastodon was formerly. a 
burrowing animal! In the evening we rode another stage, and 
crossed the Monge, another brackish stream, bearing the dregs 
of the washings of the Pampas. 
October 2nd.—We passed through Corunda, which, from the 
luxuriance of its gardens, was one of the prettiest villages I saw. 
