000, other
important towns are Cali (16,000), Buga, Cartago and Buenaventura.

CAUCASIA, or CAUCASUS, a governor-generalship of Russia, occupying the
isthmus between the Black Sea and the Sea of Azov on the west and the
Caspian Sea on the east, as well as portions of the Armenian highlands.
Its northern boundary is the Kuma-Manych depression, a succession of
narrow, half-desiccated lakes and river-beds, only temporarily filled
with water and connecting the Manych, a tributary of the Don, with the
Kuma, which flows into the Caspian. This depression is supposed to be a
relic of the former post-Pliocene connexion between the Black Sea and
the Caspian, and is accepted by most geographers as the natural frontier
between Europe and Asia, while others make the dividing-line coincide
with the principal water-parting of the Caucasus mountain system. The
southern boundary of Caucasia is in part coincident with the river Aras
(Araxes), in part purely conventional and political. It was shifted
several times during the 19th century, but now runs from a point on the
Black Sea, some 20 m. south of Batum, in a south-easterly and easterly
direction to Mt. Ararat, and thence along the Aras to within 30 m. of
its confluence with the Kura, where it once more turns south-east, and
eventually strikes the Caspian at Astara (30 deg. 35' N.). This large
territory, covering an area of 180,843 sq. m., and having in 1897
9,248,695 inhabitants (51 per sq. m.), may be divided into four natural
zones or sections:--(i.) the plains north of the Caucasus mountains,
comprising the administrative division of Northern Caucasia; (ii.) the
Caucasus range and the highlands of Daghestan; (iii.) the valleys of the
Rion and the Kura, between the Caucasus range and the highlands of
Armenia; and (iv.) the highlands of Armenia.

(i.) The _plains of Northern Caucasia_, which include most of the
provinces of Kuban and Terek and of the government of Stavropol, slope
gently downwards from the foot of the Caucasus range towards the
Kuma-Manych depression. It is only in their centre that they reach
altitudes of as much as 2000-2500 ft. e.g. in the Stavropol "plateau,"
which stretches northwards, separating the tributaries of the Kuban
from those of the Terek and the Kuma. Towards the foothills of the
Caucasus they are clothed with thick forests, while in the west they
merge into the steppes of south Russia or end in marshy ground, choked
with r