Azara's Account of the Lake of Ybera. 219 



ed, that when he got to the mouth of the mine, the scene was 

 very little better ; there was such a dust, that he could not see 

 his hand before him ; large masses of rock were rolling down 

 the side of the mountain on which he stood, and he heard 

 them coming, and rushing past him, without being able to see 

 how to avoid them, and be therefore stood his ground, afraid 

 to move. In almost all the mines which we visited in Chili, 

 we witnessed the awful effects of these earthquakes, and it was 

 astonishing to observe how severely the mountains had been 

 shaken. — Captain Head's Rough Notes on the Pampas. Lon- 

 don, 1826. 



4. Account of the Lake of Ybera, formed by infiltration from 

 the River Parana. By M. Azara. 

 On the river Parana, there is a chain of rocks situated in 27° 

 £7' 10" of north lat. and 59° of west long. ; but the passage is 

 always free for small boats, when the river is large, so that 

 the Parana is navigable from the confluence of the Ygazu to 

 the sea. Near this is the Lake Ybera. It is thirty leagues 

 wide to the north, parallel to the Parana, to which it closely 

 approaches, without having any visible communication with 

 this river. It extends thirty leagues to the south, where it 

 forms what is called the gorge of Yuquicua, and afterwards, 

 widening in proportion as it advances to the south, it termi- 

 nates by forming the river Miriuay, which is a considerable 

 one, and which throws itself into the Uruquay. From Yu- 

 quicua the banks of the Ybera have a westerly direction for 

 thirty leagues, and there issue from it three rivers, viz. that 

 of St Lucie, the Corrientes, and the Bateles, which one can 

 never pass, and which throws itself into the Parana. The 

 lake of Ybera receives neither river, nor brook, nor spring. 

 It subsists the whole year without almost any variation ; and 

 it is in a great measure filled with aquatic plants, and even 

 with some trees. It is kept up, however, by the simple fil- 

 tration of the waters of the Parana, which is without example 

 in any other part of the world. This filtration furnishes not 

 only the water of four large rivers, but also that which is 

 carried off by evaporation from a surface of at least 4000 



