tine frontier and are
sources of the two rivers of the same names. Below the Bio-Bio river
there is a line of large picturesque lakes extending from the province
of Cautin, south through that of Llanquihue, corresponding in
character and position to the dry lacustrine depressions extending
northward in the same valley. They lie on the eastern side near the
Cordilleras, and serve the purpose of great reservoirs for the
excessive precipitation of rain and snow on their western slopes. With
one exception they all drain westward into the Pacific through short
and partly navigable rivers, and some of the lakes are also utilized
for steamship navigation. These lakes are Villarica on the southern
frontier of Cautin, Rinihue and Ranco in Valdivia, and Puyehue,
Rupanco, Llanquihue and Todos los Santos in Llanquihue. The largest of
the number are Lakes Ranco and Llanquihue, the former with an
estimated area of 200 sq. m. and the latter of 300 sq. m. Lake Todos
los Santos is situated well within the Andean foothills north-east of
Puerto Montt and at an elevation of 509 ft., considerably above that
of the other lakes, Lake Ranco being 230 ft. above sea-level. The
great Andean lakes of General Paz (near the 44th parallel), Buenos
Aires (in lat. 46 deg. 30' S.), Pueyrredon, or Cpchrane (47 deg. 15' S.)
and San Martin (49 deg. S.), lie partly within Chilean territory. In the
extreme south are Lagoa Blanca, a large fresh-water lake in lat. 52 deg.
30' S., and two large inland salt-water sounds, or lagoons, called
Otway Water and Skyring Water, connected by FitzRoy Passage.

_Geology._--Chile may be divided longitudinally into two regions which
differ from each other in their geological structure. Along the coast
lies a belt of granite and schist overlaid unconformably by Cretaceous
and Tertiary deposits; inland the mountains are formed chiefly of
folded Mesozoic beds, together with volcanic rocks of later date. The
great longitudinal valley of Chile runs approximately, but only
approximately, along the boundary between the two zones. Towards the
north the coastal zone disappears beneath the sea and the Andean zone
reaches to the shore. The ancient rocks which form the most
characteristic feature of the former do indeed occur upon the coast of
Peru, but in the north of Chile they are found only in isolated masses
standing close to the shore or, as at Mejillones, projec