s even precipitous. In the middle division, or from the mouth of
the Voronezh to the point where it makes its nearest approach to the
Volga, the stream cuts its way for the most part through Cretaceous
rocks, which in many places rise on either side in steep and elevated
banks, and at intervals encroach on the river-bed. A short distance
below the town of Rostov it breaks up into several channels, of which
the largest and most southern retains the name of the river. Before it
receives the Voronezh the Don has a breadth of 500 to 700, or even in a
few places 1000 ft., while its depth varies from 4 to 20 ft.; by the
time it reaches its most eastern point the depth has increased to 8-50
ft., and the ordinary breadth to 700-1000 ft., with an occasional
maximum of 1400 ft.; in the lowest division the depth is frequently 70
ft., and the breadth in many places 1870 ft. Generally speaking, the
right bank is high and the left flat and low. Shallow reaches are not
uncommon, and there are at least seven considerable shoals in the
south-western part of the course; partly owing to this cause, and partly
to the scarcity of ship-timber in the Voronezh government, the Don,
although navigable as far up as Voronezh, does not attain any great
importance as a means of communication till it reaches Kachalinskaya in
the vicinity of the Volga. From that point, or rather from Kalach, where
the railway (built in 1862) from the Volga has its western terminus, the
traffic is very extensive. Of the tributaries of the river, the
Voronezh, the Khoper, the Medvyeditsa and the Donets are navigable--the
Donets having a course of 680 m., and during high water affording access
to the government of Kharkov. The Manych, another large affluent on the
left, marks the ancient line of water connexion between the Sea of Azov
and the Caspian Sea. The lower section of the Don is subject to two
annual floods, of which the earlier, known as the "cold water," is
caused by the melting of the snow in the country of the Don Cossacks,
and the later, or the "warm water," is due to the same process taking
place in the region drained by the upper parts of the stream. About the
beginning of June the river begins to subside with great rapidity; in
August the water is very low and navigation almost ceases; but
occasionally after the September rains the traffic with small craft is
again practicable. Since the middle of the 18th century there have been
five floods of extraordinar