Persian Gulf, an arm of the Indian Ocean which penetrates 650 miles north-westward between Arabia and Persia. Its breadth varies from 55 miles at the mouth to 250 miles, and the area is estimated at 77,450 sq. m., not including the islands, which are scattered over the western half, or lie close inshore along the eastern side. The chief of these islands are Ormuz, at the mouth; Kishm, 810 sq. m. in extent; and the Bahrein Islands. The Great Pearl Bank stretches along the western side from Ras Hassan to nearly half way up the gulf. On the Arabian side the coast is low and sandy, occasionally broken by mountains and cliffs; while on the Persian side it is higher and abrupt, with deep water close inshore, owing to the mountain-ranges of Fars and Laristan running close to the water's edge. The islands, mostly barren and destitute of springs, present numerous traces of volcanic eruptions. With the exception of the Shat-el-Arab (see Euphrates), the Persian Gulf receives only insignificant streams. Its eastern side offers good anchorage, either in the numerous bays or in the lee of islands. The greater portion of its southern shores now belongs to the Imam of Muscat, while the whole of the northern shore belongs to Persia. The greatest depth does not exceed 50 fathoms. The submarine telegraph cables of the government of India traverse the whole length of the Persian Gulf, and connect with the systems of Persia and India.