the Rio
Fetaleufu or Fetalauquen, its principal source being a large lake of
the same name. It flows south-west through the Andes, and then
north-west through Lake Yelcho to the Gulf of Corcovado. The Argentine
colony of the 16th of October, settled principally by Welshmen from
Chubut, is located on some of the upper tributaries of this river, in
about lat. 43 deg. S. The Palena is another river of the same character,
having its source in a large frontier lake called General Paz and
flowing for some distance through Argentine territory before crossing
into Chile. It receives one large tributary from the south, the Roo
Pico, and enters an estuary of the Gulf of Corcovado a little north of
the 44th parallel. The Frias is wholly a Chilean river, draining an
extensive Andean region between the 44th and 45th parallels and
discharging into the Puyuguapi channel, which separates Magdalena
island from the mainland. The Aisen also has its source in Argentine
territory near the 46th parallel, and drains a mountainous region as
far north as the 45th parallel, receiving numerous tributaries, and
discharging a large volume of water into the Moraleda channel in about
lat. 45 deg. 20' S. The lower course of this river is essentially an
inlet, and is navigable for a short distance. The next large river is
the Las Heras, or Baker, through which the waters of Lakes Buenos
Aires and Pueyrredon, or Cochrane, find their way to the Pacific. Both
of these large lakes are crossed by the boundary line. The Las Heras
discharges into Martinez Inlet, the northern part of a large estuary
called Baker or Calen Inlet which penetrates the mainland about 75 m.
and opens into Tarn Bay at the south-east corner of the Gulf of Penas.
Azopardo (or Merino Jarpa) island lies wholly within this great
estuary, while at its mouth lies a group of smaller islands, called
Baker Islands, which separate it from Messier Channel. The course of
the Las Heras from Lake Buenos Aires is south and south-west, the
short range of mountains in which are found the Cerros San Valentin
and Arenales forcing it southward for an outlet. Baker Inlet also
receives the waters of still another large Argentine-Chilean lake, San
Martin, whose far-reaching fjord-like arms extend from lat. 49 deg. 10'
to 48 deg. 20' S.; its north-west arm drains into the Tero, or La Pascua,
river. Lake San Martin lies in a crooked deeply cu