Mt Dindymus (Murad Dagh) marked the frontier of Mysia, and the entire valley of the Tembrogius or Tembris (Porsuk Su) was certainly included in Phrygia.
The northern half is drained by rivers which run to the Black Sea; of these the eastern ones, Porsuk Su (Tembris or Tembrogius), Seidi Su (Parthenius), Bardakchi Tchai (Xerabates), and Bayat Tchai (Alandrus), join the Sangarius, while the western,2 Taushanly Tchai (Rhyndacus) and Simav Tchai (Macestus), meet and flow into the Propontis.
The valleys of the Maeander, Hermus and Caicus facilitate communication between the plateau and the Aegean, and the descent to the Sea of Marmora along the valleys of the Tembris and Sangarius presents no difficulties.
Its tributaries are the Pursak Su (Tembris), which has its source in the Murad Dagh (Dindymus), and, after running north to Eski-shehr, flows almost due east to the Sakaria, and the Enguri Su, which joins the Sakaria a little below the junction of the `Pursak.
From Angora, and the junction for Konia; and is situated on the right bank of the Pursak Su (Tembris), a tributary of the Sakaria, at the foot of the hills that border the broad treeless valley.