106 RIO NEGRO. 
little surprised to find them, on a near approach, no higher than 
the surrounding shrubs, four or five feet. Shrubs are trimmed 
in this manner at distances of about half a mile from each other, 
and are used as guide-posts on the prairie. A similar optical effect 
is spoken of by travellers on the steppes of Russia. 
Game is most plentiful, consisting of deer, guanacoes and carias, 
cassowaries, partridges, bustards, ducks, &c. Armadillos were com- 
mon, and the ostrich was frequently seen ; porcupines are said also to 
be found. The carias were seen running about in single file, with a 
sort of halting gait. 
The soil of the Campos was mostly a mixture of clay, sand and 
small pebbles, but is destitute of vegetable mould. They have the 
practice of burning the prairies in order to produce a new crop of 
sweet and nutritious grass for the cattle. The rock of the cliff, and 
along the river where it can be seen, is a soft, gray sandstone, in 
some places so friable as to be easily crumbled between the fingers, 
while other specimens are of sufficient hardness for building stone! 
The stratification is perfectly horizontal. 
The width of the river is less than a third of a mile ; it has a rapid 
current, and a large body of water is carried by it to the ocean. The 
ordinary tide is about eight feet, and the spring tides fourteen feet. 
The current is mostly downward, although the tide is felt about ten 
miles above its mouth. The ebb sets off shore some three or four 
miles, and may be known from the discoloration of the water, which 
just without the bar is comparatively fresh. The depth at high water 
on the bar is two and a half fathoms, and the bar is a changing one. 
No springs were observed in the vicinity, or any trace of running 
water except in the river. The water from the rains collects in the 
depressions, and forms large ponds covering acres of ground, but only 
a few inches in depth. 
The time of our visit corresponded in season to our midsummer 
months, and the mean temperature was found to be 73°. The 
winters are represented as very mild; snow does fall, but it disappears 
m a few hours. Ice is seldom seen, though frosts appear to be fre- 
quent in the winter. January, February, March, and April are the 
least tempestuous months. 
The vegetation of the upland bears the marks of long continued 
droughts, in an absence of trees, and the roots of plants penetrating 
vertically. The stunted appearance of the shrubs, branching from 
their base, their branches dense, rigid and impenetrable, usually 
