JAXARTES, the Shon, of Syr Daria (i.e., Yellow River), a river of Turkestan, rising in the high table-land that stretches westward from the N. side of the Lake Sir-i-kol, opposite Issar, and falling into the Sea of Aral. It springs from many sources in the great Moohitah table-land where the lake of Sengirkool and the mountain torrents of the Terck and Karaboura ranges chiefly contribute to its origin. After leaving the mountains the Syr enters the Khokan Valley which it traverses, and where its volume is very much increased by the influx of streams on both sides. After a course of about 400 miles it enters the Khrizj-steppe at the town of Rhodien. In its passage through this desert it receives tributaries from the N. alone, the country to the S. being too flat and dry for water to collect or flow. It is here that the Syr branches off into two, formerly three, separate rivers about 250 miles from the Aral. The most northern and largest branch being the proper continuance of the original river, keeps the name Syr, while the other is called Koovan-Daria. A third branch, the most southern, called Taghiti-Daria, is now dried up. This was caused by the Khokamians, about 1815, erecting a strong dyke at the point where this branch diverged from the main stream, to prevent the inhabitants of the Khanas of Khiva from planting colonies on its banks. The river enters the Aral at Fort Kos-Aral after a course of about 1000 miles. From the general flatness of the country traversed, the Syr is very tortuous, with low banks, and its waters, as the name denotes, have a lightish yellow appearance. Its depth varies according to the season of the year; in autumn, the water being very low, and in some places dried up, while in spring its banks are overflowed. It is the intention of the Russian government to form a line of small steamers for the navigation of the Syr, which will develop the resources of its fertile banks. This river was not unknown to the ancients. Its banks were peopled by the Massagetae, with whom Cyrus the elder of Persia came into collision, about the year 530 n.c., in his attempt to extend his conquests beyond the Aral; and it was in battle with their queen Tomyris that the Persian lost his life. He founded a city on the left bank of the river called Cyreschatu, the ruins of which are said to have been discovered by recent travellers. It was next visited by the Greeks under Alexander in 329 n.c., in their invasion of Sogdiana, and a city was founded and named Alexandreia Ultima. But the ancient and modern geography of this whole country is so obscure and often contradictory, that disputes have arisen on the most important points of the subject. These ambiguities and contradictions arise from two circumstances, the inaccessibility of the place, and more particularly the peculiar and remarkable changes of the surface which occur in these parts. The Jaxartes was believed by the ancients to flow into the Caspian. There is now little doubt that the present Sea of Aral formed, at no distant period, a part of the Caspian, as the geology of the district, as well as historical evidence, clearly proves; while, from the former source, it is evident that by plutonic action the position of the rivers, as well as of these great lakes, has been very materially changed, and still is transitory.