Mar'mora, SEA OF

Mar'mora, SEA OF, the Propontis of the ancients, separating European from Asiatic Turkey, and connecting the Ægean Sea by the Dardanelles (anc. Hellaspont) with the Black Sea by the Strait of Constantinople (anc. Bosporus). It is of an oval form, is 175 miles in length by 50 in breadth, has an area of 4499 sq. m., and a maximum depth of 4250 feet. The Gulf of Ismid extends about 30 miles eastwards into Asia. The sea contains several islands, the largest of which is Marmora or Marmara (area, 50 sq. m.), famous for its quarries of marble and alabaster.