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RIO TERCERO 



sidcred 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 \st. — We started by moonlight and arrived at the 



TOXODON PLATENSIS. FOUND AT SALAUILLO. 



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 da\', searching for fossil bones. 

 Besides a perfect tooth of the Toxodon, and many scattered 

 bones, I found two immense skeletons near each other, project- 

 ing 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 



