The main body, finding its expansion southwards checked by Urartu, diverged in a south-easterly direction, and sweeping before it all the non-Aryan or Turanian tribes who were too weak to stem its progress, gradually occupied the western edge of the great plateau, where it soon became mainly represented by the two compact groups, the Persians to the south on the farthest confines of Elam, and the Medes between the Greater Zab, the Turnat, and the Caspian. It is probable that the kingdom founded by Deiokes originally included what was afterwards termed _Media Magna_ by the Graeco-Roman geographers. This sovereignty was formed by the amalgamation under a single monarch of six important tribes--the Buzo, Paraatakeni, Struchatas, Arizanti, Budii, and Magi. It extended north-westwards as far as the Kiziluzon, which formed the frontier between the Persians and the Mannai on this side. Northwards, it reached as far as Demavend; the salt desert that rendered Central Iran a barren region, furnished a natural boundary on the east; on both the south and west, the Assyrian border-lands of Ellipi, Kharkhar, and Arrapkha prevented it from extending to the chief ranges of the Zagros and Cordioan mountains. The soil, though less fertile than that of Chaldaea or of Egypt, was by no means deficient in resources. The mountains contained copper, iron, lead, some gold and silver,* several kinds of white or coloured marble,** and precious stones, such as topaz, garnets, emeralds, sapphires, cornelian, and lapis-lazuli, the latter being a substance held in the highest esteem by Eastern jewellers from time immemorial; Mount Bikni was specially celebrated for the fine specimens of this stone which were obtained there.*** Its mountains were in those days clothed with dense forests, in which the pine, the oak, and the poplar grew side by side with the eastern plane tree, the cedar, lime, elm, ash, hazel, and terebinth.**** * Rawlinson has collected traditions in reference to gold and silver mining among the mountains in the neighbourhood of Takht-i-Suleiman; one of these is still called _Zerreh- Shardn_, the mount of the _gold-washers_. ** The best known was the so-called Tauris marble quarried from the hills in the neighbourhood of Lake Urumiyah. *** The list of precious stones which Pliny tells us were found in Media, contains several kinds which we are unable to identify, _e.g_. the Zathene, the gassinades and narcissitis. Pliny calls lapis-lazuli _sapphirus_, and declares that the bright specks of pyrites it contained rendered it unsuitable for engraving. In the Assyrian inscriptions Mount Bikni, the modern Demavend, is described as a mountain of Uknu, or lapis-lazuli.