a few leagues apart. However, they do not yet blend their waters; after
proceeding side by side for some twenty or thirty miles, they again
separate and only finally; unite at a point some eighty leagues lower
down. At the beginning of our geological period their course was not
such a long one. The sea then penetrated as far as lat. 33°, and was
only arrested by the last undulations of the great plateau of secondary
formation, which descend from the mountain group of Armenia: the two
rivers entered the sea at a distance of about twenty leagues apart,
falling into a gulf bounded on the east by the last spurs of the
mountains of Iran, on the west by the sandy heights which border the
margin of the Arabian Desert.* They filled up this gulf with their
alluvial deposit, aided by the Adhem, the Diyâleh, the Kerkha, the
Karun, and other rivers, which at the end of long independent courses
became tributaries of the Tigris. The present beds of the two rivers,
connected by numerous canals, at length meet near the village of Kornah
and form one single river, the Shatt-el-Arab, which carries their waters
to the sea. The mud with which they are charged is deposited when it
reaches their mouth, and accumulates rapidly; it is said that the coast
advances about a mile every seventy years.** In its upper reaches the
Euphrates collects a number of small affluents, the most important of
which, the Kara-Su, has often been confounded with it. Near the middle
of its course, the Sadjur on the right bank carries into it the waters
of the Taurus and the Amanus, on the left bank the Balikh and the Khabur
contribute those of the Karadja-Dagh; from the mouth of the Khabur to
the sea the Euphrates receives no further affluent. The Tigris is fed on
the left by the Bitlis-Khai, the two Zabs, the Adhem, and the Diyâleh.
The Euphrates is navigable from Sumeisat, the Tigris from Mossul, both
of them almost as soon as they leave the mountains. They are subject
to annual floods, which occur when the winter snow melts on the higher
ranges of Armenia. The Tigris, which rises from the southern slope of