ble possession of
the territory. This arbitrary retention of Tacna and Arica, which became
the province of Tacna under Chilean administration, removed the frontier
still farther north, to the river Sama, which separates that province
from the remaining part of the Peruvian department of Moquegua. Starting
from the mouth of that river, in 17 deg. 57' S., the disputed boundary
follows its course in an irregular N.E. direction to its source in the
Alto do Toledo range, thence S. and E. along the water parting to the
Bolivian boundary line in the Cordillera Silillica.

_Physiography._--For purposes of general topographical description
Chile may be divided into three regions: the desert region of the
north, the central agricultural region between the provinces of
Coquimbo and Llanquihue, and the heavily-forested rainy region south
of lat. 41 deg. S. The desert region is an elevated arid plateau
descending gradually from the Andes towards the coast, where it breaks
down abruptly from elevations of 800 to 1500 ft. From the sea this
plateau escarpment has the appearance of a range of flat topped hills
closely following the coast line. The surface is made up of extensive
plains covered with sand and deposits of alkaline salts, broken by
ranges of barren hills having the appearance of spurs from the Andes,
and by irregular lateral ranges in the vicinity of the main cordillera
enclosing elevated saline plateaus. This region is rainless, barren
and inhospitable, absolutely destitute of vegetation except in some
small river valleys where irrigation is possible, and on the slopes of
some of the snow-covered peaks where the water from the melting snows
nourishes a scanty and coarse vegetation before it disappears in the
thirsty sands. It is very rich in mineral and saline deposits,
however. The eastern parts of this region lie within the higher ranges
of the Andes and include a large district awarded to Chile in 1899
(see ARGENTINA and ATACAMA). This arid, bleak area is apparently a
continuation southward of the great Bolivian _altaplanicie_, and is
known as the Puna de Atacama. Its average elevation is estimated at
11,000 to 12,000 ft. A line of volcanoes crosses it from north to
south, and extensive lava beds cover a considerable part of its
surface. Large shallow saline lakes are also characteristic features
of this region. From 28 deg. S. the spurs from the cordillera toward the