386 SMITH. 



himself. Tliis map shows as many as 15 peaks in the interior, the 

 highest of which is 253 meters, which evidently represent extinct volcanic 

 vents, and in the southern part of the island are three almost circular 

 depressions, two of which are entirely enclosed, and the third. Lake 

 Jiwata, is connected 'with the sea by a small opening. In tliis opening 

 are two or three islets and it is quite evident that this basin was also 

 once entirely enclosed, the narrow rim of it having been broken through 

 by the sea. 



My own observations in Sulu consist of a trip across the Island of 

 Sulu from the town of Jolo to Meimbun; the ascent of Mount Dajo; 

 some reconnaissance on the outskirts of Jolo; a short trip of two or 

 three miles on the coast of the Island of Siasi ; a short excursion of a few 

 hundred yards from the coast on the Island of Lapac; an ascent of the 

 high peak on Bongao Island ; and such observations as I could make from 

 the launch which sldrted many of the small islands as we went through 

 the Archipelago. 



The Island of Sulu, as far as 1 could see, is almost entirely blanketed 

 by volcanic material, either basalt, tulf, or ash. I saw no active volcanoes 

 in Sulu, but it is reported that there are hot springs at Si'it Lake. The 

 island is studded with extinct or dormant cones, the most prominent 

 of which, and at the same time the most interesting from an historic 

 standpoint, is Bud Dajo, ten or eleven kilometers southeast of the town 

 of Jolo. This is a beautifid cinder cone now covered with luxuriant 

 vegetation. A photograph is shown in my first paper, Narrative of the 

 Expedition.^* The diameter of the crater is about 480 meters. It is 

 almost circular and is broken down on the southeast side, where a small 

 stream issues. A spring, which feeds this stream, is located almost • 

 in the center of the crater. The panorama obtained from the rim is one 

 of the most beautiful I have ever seen. Ever}Tvhere are extinct cones, 

 the side of which are now covered either with forests or cogon grass, and 

 in the valleys between are found many haciendas of tapioca. It would 

 be extremely desirable to know the nature of the formation below the 

 mantle of volcanic material. The streams as yet have not cut very 

 extensivel}', so that we do not know just at what depth the sedimentary 

 formations are to be found. However, should we not find sandstones 

 and shales it is quite reasonable to suppose that drilling in the vicinity 

 of Jolo woixld tap a loose formation of volcanic material which carries 

 water. I know of no economic deposits being worked on this island. 



The Island of Siasi is covered with a mantle of volcanic material 

 weathered to a considerable depth. Lapac is the same. Tawi Tawi 

 seems to be like the rest. Bongao Island, at the extreme southwest end 

 of Tawi Tawi, is made up largely of tilted beds of sandstone and con- 



"THs Journal, Sec. A (1908), 3, 473. 



