(τὸ Ἴσιον ὄρος
, Ptol. 4.7.5
), a mountain, or rather a ridge of highlands rising gradually on its western side, but steep and escarped towards the east, on the coast of Aethiopia, and in the Regio Troglodytica.
It was seated in lat. 20° 1‘ N., a little to the southward of the headland Mnemium (Μνημεῖον ἄκρον, Ptol. 4.5.7
), and SW. of Berenice and the Sinus Immundus (Foul Bay
). Mons Isius answers to the modern Ras-el-Dwaer.
Strabo, indeed (xvii. p. 770), places this eminence further to the south, and says that it was so called from a temple of Isis near its summit.