couple of silk shirts, one pair of hob-nailed shoes with leggings, and
one pair of laced leather boots coming nearly to the knee. Both the
naturalists told me that it was well to have either the boots or
leggings as a protection against snake-bites, and I also had gauntlets
because of the mosquitoes and sand-flies. We intended where possible
to live on what we could get from time to time in the country, but we
took some United States Army emergency rations, and also ninety cans,
each containing a day's provisions for five men, made up by Fiala.

The trip I proposed to take can be understood only if there is a
slight knowledge of South American topography. The great mountain
chain of the Andes extends down the entire length of the western
coast, so close to the Pacific Ocean that no rivers of any importance
enter it. The rivers of South America drain into the Atlantic.
Southernmost South America, including over half of the territory of
the Argentine Republic, consists chiefly of a cool, open plains
country. Northward of this country, and eastward of the Andes, lies
the great bulk of the South American continent, which is included in
the tropical and the subtropical regions. Most of this territory is
Brazilian. Aside from certain relatively small stretches drained by
coast rivers, this immense region of tropical and subtropical America
east of the Andes is drained by the three great river systems of the
Plate, the Amazon, and the Orinoco. At their headwaters the Amazon and
the Orinoco systems are actually connected by a sluggish natural
canal. The headwaters of the northern affluents of the Paraguay and
the southern affluents of the Amazon are sundered by a stretch of high
land, which toward the east broadens out into the central plateau of
Brazil. Geologically this is a very ancient region, having appeared
above the waters before the dawning of the age of reptiles, or,
indeed, of any true land vertebrates on the globe. This plateau is a