RECONNAISSANCE OF SOUTHEASTERN LUZON. 457 



the Ragay Coast Hills in general have escarpment features, ahO the Binall 

 hills, somewhat conical in form which give their higher portions a broken 

 appearance, are remnants of sedimentary beds which have been weathered 

 and eroded away from the intei-vening areas. The northeastern border of 

 the iSagay Coast Hills, in their central portion, descends to the Bicol 

 Valley. An annof this lowland extends through the Ragay Hill^ to the 

 coast at Pasacao. This low pass has been noted both by Jagor and von 

 Drasche, who state that it pi'obably was onc(j a seaway. It affords an easy 

 route of (ommunication from tlie country around Nueva Caceres to 

 Ragay Gulf. 



] During Spanish times some work was done in cutting a canal to connect 

 the head of the stream which enters the sea at Pasacao with a tributary of the 

 Bicol River. This undertaking was abandoned because it was expensive, and 

 it is doubtful if the facilities for transportation in small boats would ever 

 justify the undertaking. 



The northern termination of the Ragay Coast Hills blends with the 

 slope of the cordillera; the southern, where it joins the cordillera, is 

 marked by the contrast in topographic feature resulting from the ero- 

 sion of sedimentary beds and igneous rocks. 



Bicol Valley. — This area is lowland drained by the Bicol River. 

 Its southern portion has swift-flowing streams, tributary to Bato Lake. 

 The river is sluggish when it leaves this lake and is bordered by areas 

 which aie swampy and ovei-flow dtiring the flood season of the river. 

 The shores of the lake are subject to overflow, and a considerable por- 

 tion of its surface is covered with a gi-owth of aquatic vegetation. 



Where the Bicol River impinges on the Ragay Coast Hills at a point 

 about half-way between Bato Lake and Nueva Caceres, there are some 

 slight rapids. The channel deepens below this point. Nine and one- 

 half feet (about 3 meters) of water, according to the Coast and Geo- 

 detic Survey chart, are found at the wharf in Nueva Caceres. The 

 mouth of the river contains bars whicli are shifting, and the water near 

 thie shores of San Mig-uel Bay at the mouth of the valley is very shallow. 



There are but few minor accidents in the topography of the Bicol Val- 

 ley. It appears probable that Bato Lake and the rapids between it and 

 Nueva Caceres owe their origin to difl'erential elevation. The head of the 

 Bicol Valley appears to have been aggraded by the detrital material 

 from the slopes of Mayon Volcano. There is an area of lowland on 

 the coast at Legaspi and bordering Albay Gulf. Between this lowland 

 and the head of tlie Bicol Valley the lowest elevation of the divide is 

 about 100 meters. It seems probable that there was once a seaway be- 

 tween San Miguel Bay and Albay Gulf, which has been closed by local 

 eruptions, the gTowth of Mayon Volcano, and regional elevation. ' 



Eastern Cordillera. — The isthmian and peninsular portions of 'I'a- 

 yabas Province have a northwestern-southeastern structure; They are 



