Morontobara was an ancient name for Manora Island, located In Karachi, Pakistan.
Alexander the Great camped to prepare a fleet for Babylonia after his campaign in the Indus valley; 'Morontobara' island (ancient Manora Island near Karachi harbour), from where Alexander's admiral Nearchus set sail; and Barbarikon (Βαρβαρικόν), a port of the Indo-Greek Bactrian kingdom.
References
Morontobara Wikipedia(Text) CC BY-SA