THE VOYAGE OF THE BEAGLE 139 



also the opposite shore. The view would resemble that of a 

 great lake, if it were not for the linear-shaped islets, which 

 alone give the idea of running water. The cliffs are the most 

 picturesque part; sometimes they are absolutely perpendicu- 

 lar, and of a red colour; at other times in large 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 

 what a distance it travels; and from how vast a territory 

 it drains the great body of fresh water which flows past 

 your feet. 



For many leagues north and south of San Nicolas and 

 Rozario, the country is really level. Scarcely anything which 

 travellers 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 distant. 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 ist. We started by moonlight and arrived at the 

 Rio Tercero by sunrise. The river is also called the Sala- 

 dillo, 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 spe- 

 cies with that, which formerly must have inhabited the Cor- 

 dillera 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: 



