1 2 FERGUSON. 



small, irregular liills having the ai>i)earance of "mouaduoeks ;" and the 

 third, an irregular fringe of mangrove swamps together with the smootli, 

 flat stretches probably formed by this agency. 



The submarine contours of Nin Bay suggest depression rather than 

 elevation and this would be in accord with the topography of the coastal 

 plain. An elevation of 35 meters ■would connect Masbate with Panay 

 by a narrow ridge containing Jinototo and the two Zapatos Islands, 

 which would stand out as peaks above the rest of the ridge. !Mr. 

 Worcester,^" reasoning from zoological evidence, suggested that JIasbate, 

 Panay, Guimaras, and Negros were formerly connected, and at least as 

 far as concerns Masbate and Panay, the physiographic evidence confirms 

 this. Dr. Becker,^^ following this and from a study of the cliarts of 

 these waters, suggests the separation of these islands by the submergence 

 of a coastal peneplain. The prolongation of the southern fork of Mas- 

 bate does not form a continuation of the westei-n line of the hills of 

 Panay, but is offset to the east so that the Jintotolo Channel is S-shaped. 

 A deep channel extends from the moiith of the Panay River east of the 

 connecting ridge, apparently a submarine prolongation of that river, and 

 in that case furnishing further evidence of depression. This channel 

 follows a northeasterly course as far as Jintotolo Island, where it makes 

 a sharp turn and runs about S. 30° E., roughly parallel to the main 

 prong of Masbate. 



THE SOUTHWESTERN RANGE. 



Leaving Port Mandaon and traveling eastward across the island, 

 one passes through 5 or 6 kilometers of gently rolling country — the 

 same plain as that crossed in coming from the north — and then follows 

 the valley of the Tagpoc to the mountain range. A large hill of ir- 

 regular outline stands on the north, while to the south a range of low 

 hills extends out from the main range in a northwesterly direction. 

 The upper part of the main ridge, here known as Mount Gantal, is very 

 steep, rising from an elevation of about 200 meters where the main 

 part of the ascent begins to about 550 meters at the pass, less than a 

 kilometer distant. At this point the axis of the range has a direction 

 of N. 10° E., but farther south it resumes its normal northwesterly 

 direction. 



The underlying rocks in the lower part are grits or pyroclastic rocks 

 much decomposed, with one outcrop of a black slate. The summit of 

 the ridge shows fine-grained igneous rocks also much altered, while a 

 red slate outcrops on a spur extending eastward from the summit. 

 After a steep descent on the eastern side a rough plain studded witli 

 small, irregular hills is reached. The Bxirakai Eiver, having its head- 



^"Proc. V. S. Nat. Mus. (1898), 20, 578. 



" U. S. Geol. Sur., 21st Ann. Rep. (1900), Pt. 3, 51)7. 



