IASTUS a river mentioned by Ptolemy (6.14.2) as falling into the Caspian between the Jaik and the Oxus.
It is only safe to call it one of the numerous rivers of Independent Tartary. [R.G.L]
Dictionary of Greek and Roman Geography, illustrated by numerous engravings on wood. William Smith, LLD. London. Walton and Maberly, Upper Gower Street and Ivy Lane, Paternoster Row; John Murray, Albemarle Street. 1854.