ll
islands on the northern coast, and a few small islands so near the
mainland as to form sheltered harbours, as at Cartagena. The largest
of these islands is Baru, lying immediately south of the entrance to
Cartagena harbour. North-west of Colombia in the Caribbean Sea are
several small islands belonging to the republic, two of which (Great
and Little Corn Is.) lie very near the coast of Nicaragua. The largest
and most important of these islands is Vieja Providencia (Old
Providence), 120 m. off the Mosquito Coast, 4-1/2 m. long, which
supports a small population.

Rivers.

The rivers of Colombia may be divided, for convenience of description,
into three general classes according to the destination of their
waters, the Pacific, Caribbean and Atlantic--the last reaching their
destination through the Amazon and Orinoco. Of these, the Caribbean
rivers are of the greatest economic importance to the country, though
those of the eastern plains may at some time become nearly as
important as transportation routes in a region possessing forest
products of great importance and rich in agricultural and pastoral
possibilities. It is worthy of note that the principal rivers of these
three classes--the Patia, Cauca, Magdalena, Caqueta and Putumayo--all
have their sources on the high plateaus of southern Colombia and
within a comparatively limited area. The Pacific coast rivers are
numerous, and discharge a very large volume of water into the ocean in
proportion to the area of their drainage basins, because of the heavy
rainfall on the western slopes of the Coast range. The proximity of
this range to the coast limits them to short, precipitous courses,
with comparatively short navigable channels. The principal rivers of
this group, starting from the southern frontier, are the Mira, Patia,
Iscuande, Micai, Buenaventura or Dagua, San Juan and Baudo. The Mira
has its principal sources in Ecuador, and for a short distance forms
the boundary line between the two republics, but its outlets and
navigable channel are within Colombia. It has a large delta in
proportion to the length of the river, which is visible evidence of
the very large quantity of material brought down from the neighbouring
mountain slopes. The Patia is the longest river of the Pacific group,
and is the only one having its sources on the eastern side of the
Western Cordillera. It is formed by t