ing—at least its commencement—was the grand event from which the civil era of Siam dates—viz. the introduction of the sacred Buddhist canon from Ceylon in the seventh century. The general appearance of the worn stairways, and the dilapidated condition of the city, slowly mouldering under the destructive encroachments of a tropical jungle, would seem to indicate great age. Yet the mediæval narrative of Cambodian travel by a Chinese officer, late in the thirteenth century, recently translated by M. Remusat, contains no allusion to this great temple, which has induced some to conclude that the building belongs to a later period. In 1570 A. D. a Portuguese refugee from Japan refers to these "ruins" and the inscriptions thereon as being in "an unknown tongue."
III. THE THIRD BASIN—VALLEY OF THE
MEKONG.
The hill-country which separates the valley of Siam from that of the Mekong (or Mekaung)—known in its lower course as the Cambodian River—is of moderate elevation and the boundary-lines not well defined.
The Mekong is one of the most remarkable streams of Asia. It rises in Thibet, passes through Western Yunnan parallel with the Yangtse and Salween, till, breaking through the mountains not far from each other, the Yangtse flows across
