The sediments of the East Indian Archipelago, owing to the complicated topography of the land and sea bottom, vary greatly in character in different areas. In the shallow Java Sea they are relatively fine-grained and rich in volcanic debris on the south side near Java, and relatively coarse-grained and rich in quartz on the north side near Borneo. The sediments of deep water are similar to sediments in deep water in other parts of the ocean, though in general they contain less calcium carbonate, owing in part to the relatively large amount of terrigenous debris they contain. The calcium carbonate content of the sediments decreases with depth of water from an average of about 50 per cent for sediments in water less than 500 meters deep to less than 5 per cent for water mor than 5000 meters deep. In areas in which the sea floor slopes more than 5°, the calcium carbonate content is greater at depths of 2500 to 3500 meters than at depths of 1500 to 2500 meters, perhaps owing to slumping of the sediments. The sediments of Kaoe Bay contain hydrogen sulphide and iron sulphide. They also are rich in organic matter and black in color. Evidently, like in the Black sea and some of the Norwegian fiords, a condition of stagnation prevails in this bay, which is 500 meters deep and whose connection with the sea is only 50 meters deep.