Pulau Musala or Musalar lies in the W approach to Teluk Tapanuli. At its NW end is a conical mountain, about 451m high, with a prominent tree on its summit. There is a remarkable waterfall at the NW end of the island issuing from a hill with an elevation of 55m; it is a good mark when approaching from NW.
The coast from Ujung Batumamak (Batu Mamak) , the SW extremity of Teluk Tapanuli, trends in a S direction for about 49 miles to Tanjung Tabujung (Tabu-yung). There is a reef, with a depth of 3.7m, lying about 0.75 mile offshore, 13 miles S of Ujung Batumamak.
Pulau Bintanah, low and fringed by a reef, should be given a wide berth. From Pulau Bintanah, a chain of reefs and shoals, some of which dry, extends 32 miles to the S. The positions of these dangers may best be seen on the chart.
Sirene Reefs, one of the outermost dangers in this locality, consist of four heads, of which the westernmost and the southernmost, with 0.9m of water, sometimes break; there are depths of 1.4 and 6.9m on the other two patches.
Pulau Sarangbaung lies 10.5 miles NNE of the N extremity of Pulau Nias. There is a break in the reef on the SE side where boats can land at a village. The island is overgrown with coconuts and is visible for 12 miles.
Pulau Wunga, about 8 NM S of Pulau Mausi, is low andcovered with coconut trees. A large conspicuous tree, visible for 16 miles, is located on a small elevationnear the N end. The reef extending from the N side of the island is ordinarily marked by high rollers; on the S side ...