PHYSIOGRAPHY OF THE PHILIPPINE ISLANDS. 11 



and fringed with coral reefs and mangrove swamps. Near the western 

 point there is a smaller bay reaching to the southeast about 2 kilometers 

 and continued inland in a large mangrove swamp. Talisay Point at 

 the southern side of the entrance to the bay is low and fringed with 

 mangroves, with a coral reef extending out about half a kilometer. 



Port Mandaon is the third portion of the bay, a narrow stretch of 

 water extending nearly north and south, into which flow the Mandaon 

 and Tagpoc Elvers, as well as several smaller streams. The deepest 

 channel is on the western side under the hills east of Mandaon. The 

 maximum depth reached in this inner bay is 7^ meters at a point near 

 the western shore, about 2 kilometers north of the mouth. Wide mud 

 flats and large mangrove swamps occur on the eastern shore and at the 

 northern and southern ends. The narrow strait connecting Port Man- 

 daon with the outer bay is of interest because of its depth. Just inside 

 of Sanig Point the soundings show a depth of from 3 to 6 meters; 

 however, four are encountered in the narrowest part of the strait, giving 

 13, 15, 16, and 17 meters; outside in Mn Bay the water again shoals 

 rapidly to 3 meters. This deep "pothole" and the deep channel between 

 Kamasusu and Puro Islands seem to represent old river channels and 

 consequently imply a considerable amount of submergence, 20 meters at 

 the least. The "pothole" between Gapus Peninsula and Mandaon Point 

 seems to be all that remains of a large stream valley. The broader 

 stretches have silted up, while the former gorge, now the strait, has been 

 kept open through tidal scour.. It is not possible to venture any opinion 

 as to the courses of these two submerged streams or as to what led to the 

 cutting of canyons through the basalt ridge instead of their following 

 the broad southwesterly valley now marked by Loog Bay. In all prob- 

 ability the conditions were not unlike those in the Lanang district, 

 where Assuring in two directions has influenced drainage readjustments. 



THE COUNTRY SOUTH OF NIK BAY. 



A fine view of the country to the south may be obtained from Kama- 

 susu Peak, this view extending as far as the Zapatos Islands, small 

 islets between Masbate and Panay. As far as can be seen, a narrow 

 and regular range of fairly high mountains extends to the southwest. 

 These grade down to a constantly narrowing plain on the east. This 

 plain, except possibly for the outer fringe where the mangroves have 

 been at work as a land-forming agency, does not appear to be a 

 coastal plain in the true sense of the word, but rather a plain of erosion, 

 terrestrial, or marine, in part covered by wash from the hills. 



The central range rises without foothills and the plain below may be 

 roughly divided into three belts, the first with smooth outlines where the 

 wash from the hills has covered previous irregularities ; the second, grad- 

 ing into the first and in places reaching the sea, a plain broken by 



