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.
ASTARABAD, the capital of the province, is situated on the Astar, a small tributary of the Kara Su (Black river), which flows into the Caspian Sea 20 m.
There was a time in the post-Pliocene Age when a long Aral gulf of the Caspian Sea protruded eastwards nearly as far as the longitude of Merv, covering the Kara Kum sands, but not the Kara Kum plateau to the north of the sands, which is separated from the sands by a distinct sea beach.
The opinion that Lake Aral periodically disappeared, which was for a long time countenanced by Western geographers, loses more and more probability now that it is evident that at a relatively recent period the Caspian Sea extended much farther eastward than it does now, and that Lake Aral communicated with it through the Sary-kamysh depression.
The hydrography of the Caspian Sea has been studied by von Baer, by N.
Nub II., in order to retain at least a nominal sway over those Afghan territories, confirmed him in his high position and even invested Sabuktagin's son Mahmud with the governorship of Khorasan, in reward for the powerful help they had given him in his desperate struggles with a confederation of disaffected nobles of Bokhara under the leadership of Fa'iq and the troops of the Dailamites, a dynasty that had arisen on the shores of the Caspian Sea and wrested already from the hands of the Samanids all their western provinces.
The depression westward of the Caspian and Aral basins, and the original connexion of these seas, have also come under the close investigation of Russian scientists, with the result that the theory of an ancient connexion between the Oxus and the Caspian has been displaced by the more recent hypothesis of an extension of the Caspian Sea eastwards into Trans-Caspian territory within the postPleiocene age.
KALMUCK, or Kalmyk Steppe, a territory or reservation belonging to the Kalmuck or Kalmyk Tatars, in the Russian government of Astrakhan, bounded by the Volga on the N.E., the Manych on the S.W., the Caspian Sea on the E., and the territory of the Don Cossacks on the N.W.
It is the centre of caravan routes leading to the Caspian Sea and the Uralsk province.
East of the Caspian Sea and beginning at Has an Kuli Bay the river Atrek serves as the frontier as far as Chat.