Sibutu lies in a little group of the same name, situated between the Tawi-tawi Group and Borneo and at a distance of about 15 miles from each. The Sibutu Passage separates it from Manuk-manka, the southernmost island of the Tawi-tawi Group, and the Alice Channel from Borneo. This island did not lie within the limits of the Philippine Islands as defined in the Treaty of Peace of December 10, 1898. It was ceded by Spain with Kagayan Sulu, by a separate treaty in November, 1900. Its close proximity to Borneo renders it a convenient stopping place for small Moro boats navigating between Borneo and Sulu. Sitanki, an island and town, is the trade center of this group, and has just lately been made an open port. ISLAND OF SULU GEOGRAPHICAL FEATURES Sulu is an island of irregular shape and among the islands of the Archipelago is next in size to Basilan. Its longest diameter runs east and west and approximates 37 miles, while its average length does not exceed 32 miles. Its greatest width is 14 miles and its average width about 10 miles. The main structure of the island is volcanic, but it is surrounded with a coral reef formation, which is most extensive in the bays and on the south. Two indentations of the northern shore at Jolo and Si'it and two corresponding indentations of the southern shore at Maymbung and Tu'tu', divide the island into three parts--western, middle, and eastern. The Bay of Jolo is quite open and faces the northwest. It is very shallow near the shore and its head constitutes the roadstead of Jolo. The Bay of Maymbung is a deeper indentation, but it is narrower and shallower than the Bay of Jolo. The town of Maymbung lies at the head of the bay and is about 9 miles south of Jolo in a direct line. The Bays of Si'it and Tu'tu' indent the island to such an extent as to leave only a neck of land, less than 4 miles wide, connecting the middle and eastern parts of the island. The settlement of Si'it lies at the head of the bay and in the immediate vicinity of a small lake of the same name. The shores of the Bay of Tu'tu' are marshy and are covered with mangrove trees. The bay is very shallow to a considerable distance from shore. Tu'tu' is the principal settlement near the head of the bay. The backbone of the island is a mountain range which runs east and west and lies nearer to the northern shore. The highest point is Mount Tumangtangis, at the western extremity of the range. This mountain reaches a height of 853 meters above sea level and descends very rapidly to the western coast near Timahu. A spur of the mountain terminates in Point Pugut at the northwestern extremity of the island. [6]