The Aegean itself is naturally divided by the island-chains and the ridges from which they rise into a series of basins or troughs, the deepest of which is that in the north, extending from the coast of Thessaly to the Gulf of Saros, and demarcated southward by the Northern Sporades, Lemnos, Imbros and the peninsula of Gallipoli.
To these must be added the Turkish islands in the Aegean usually reckoned to Europe, that is, Thasos, Samothrace, Imbros and, in the extreme south, Crete or Candia.
The north-eastern portion of the Aegean, owing to its proximity to the coast of Thrace, was known as the Thracian Sea, and in this were situated the islands of Thasos, Samothrace and Imbros.
Imbros, Samothrace and Tenedos had remained Turkish.
Hamilton made Imbros his headquarters, and troops also were sometimes collected there owing to its vicinity both to Helles and to Anzac. Within the Dardanelles the battleship " Goliath " had been torpedoed by the Turkish destroyer " Muavenet-i-Milliye " on May 13; on the other hand British submarines were performing invaluable service, diving under the mine-fields, causing havoc amongst enemy craft in the channel itself and higher up, and threatening Ottoman communications with the peninsula.