ir fertility. This plain is of varying width, and on some parts of
the coast it disappears altogether. In Rio Grande do Sul, where two
large lakes have been created by uplifted sand beaches, the coastal
plain widens greatly, and is merged in an extensive open, rolling
grassy plain, traversed by ridges of low hills (_cuchillas_), similar
to the neighbouring republic of Uruguay. The western part of this
plain is drained by the Uruguay and its tributaries, which places it
within the river Plate (La Plata) basin.

The two great river basins of the Amazon-Tocantins and La Plata
comprise within themselves, approximately, three-fifths of the total
area of Brazil. Large areas of these great river plains are annually
flooded, the flood-plains of the Amazon extending nearly across the
whole country and comprising thousands of square miles. The Amazon
plain is heavily forested and has a slope of less than one inch to the
mile within Brazilian territory--one competent authority placing it at
about one-fifth of an inch per mile. The La Plata basin is less
heavily wooded, its surface more varied, and its Brazilian part stands
at a much higher elevation.

Of the two highland regions of Brazil, that of the northern slope of
the Amazon basin belongs physically to the isolated mountain system
extending eastward from the Negro and Orinoco to the Atlantic, the
water-parting of which forms the boundary line between the Guianas and
Brazil. The culminating point is near the western extremity of this
chain and its altitude is estimated at 8500 ft. The ranges gradually
diminish in elevation towards the east, the highest point of the
Tumuc-Humac range, on the frontier of French Guiana, being about 2600
ft. The Brazilian plateau slopes southward and eastward, traversed by
broken ranges of low mountains and deeply eroded by river courses. The
table-topped hills of Almeyrin (or Almeirim) and Erere, which lie near
the lower Amazon and rise to heights of 800 and 900 ft., are generally
considered the southernmost margin of this plateau, though Agassiz and
others describe them as remains of a great sandstone sheet which once
covered the entire Amazon valley. Its general elevation has been
estimated to be about 2000 ft. It is a stony, semi-arid region, thinly
wooded, having good grazing _campos_ in its extreme western section.
Its semi-arid character is due to the mountain ranges on i