er valley.]

The most pronounced types of the identity of a country with a river
valley are found where strongly marked geographical boundaries, like
deserts and mountains, emphasize the inner unity of the basins by
accentuating their isolation from without. This is especially the case
in high mountain regions; here canton or commune or county coincides
with the river valley. Population hugs the margins of the streams where
alone is soil fit for cultivation, and fairly level land suitable for
dwellings. Above are the unoccupied heights, at once barrier and
boundary. In the Alps, Salzburg is approximately identical with the
valley of the Salzach, Uri with that of the Reuss, the Valais with the
upper Rhone, the Engadine with the upper Inn, Glarus with the Linth,
Graubuenden or Grisons with the upper Rhine, Valtellina with the Adda. So
in the great upheaved area of the Himalayas, the state of Kashmir was
originally the valley of the upper Jhelam River, while Assam, in its
correct delimitation, is the valley of the Brahmaputra between the
Himalayan gorge and the swamps of Bengal.[691]

In mountain regions which are also arid, the identity of a district with
a stream basin becomes yet more pronounced, because here population must
gather about the common water supply, must organize to secure its fair
distribution, and cooperate in the construction of irrigation channels
to make the distribution as economical and effective as possible. Thus
in Chinese Turkestan, the districts of Yarkand, Kashgar, Aksu and
Kut-sha are identical with as many mountain tributaries of the Tarim,
whose basin in turn comprises almost the whole of Chinese Turkestan.

[Sidenote: Enclosed river valleys.]

In all such desert and mountain-rimmed valleys, the central stream
attracts to its narrow hem of alluvial soil the majority of the
population, determines the course of the main highroad, and is itself
often the only route through the encompassing barriers. Hence the
importance attached to the river by the inhabitants, an importance
reflected in the fact that the river often gives its name to the whole
district. To the most ancient Greeks _Aigiptos_ meant the river, whose
name was later transferred to the whole land; for the narrow arable
strip which constituted Egypt was "the gift of the Nile." The Aryans,
descending into India through the mountains on its northwest border,
gave the name of _Sindhu_, "the flood" or "the ocean," to the first
great r