23,5 Dicker son: Baguio Plateau 421 



of 500 meters in four or five plunges. In some places the walls are per- 

 pendicular. The surface of this plateau is very much like that at Haight's, 

 Pauai, near kilometer 57, but owing to the heavy timber of the mossy-forest 

 type it is difficult to make out the exact configuration of the surface 

 (Plate 4). There is a fairly level area on the summit and in places in 

 the rainy season standing water is to be noted and there is more or less 

 swampy ground there. This has given rise to the tradition of a lake 

 on top of Mount Data. At the time of my visit at the beginning of the 

 rainy season I saw nothing which I could call a lake. Another point which 

 has been exaggerated with reference to this mountain is the limestone 

 on it. The only limestone that I saw on or about the mountain was a small 

 residual patch of badly weathered limestone (Malumbang?) on the south- 

 east slope very close to the Bontoc trail at an elevation of approximately 

 2,040 meters (6,800 feet). 



At the extreme north end of this plateau there is a high rock from which 

 the best panorama I have ever had in the Philippines is obtained. This 

 rock is made up of agglomerate with a considerable amount of water- worn 

 bowlders firmly cemented in an andesite matrix. There is no question in 

 my mind that Mount Data is to be correlated with the Baguio Plateau. 



Kilometer 81. — At about kilometer 81 on the Baguio north trail and 

 0.5 kilometer to the east of the trail there is a small plateau remnant with 

 a remarkable "hanging valley" as shown in the accompanying photograph 

 (Plate 4). The topography of this plateau remnant is distinctly old age 

 or at least very mature,, and at the south end there are a precipitous 

 cliff and a large slide. In the upper portion of this slide there is an 

 excellent section which shows one interesting feature; namely, an old 

 buried soil about 1.5 meters thick, which at a distance has the appearance 

 of a coal seam. A sample of this was obtained and proved to be merely 

 a heavy deposit of humus. It is not even peat. There is about a 

 meter of sand and tuff above this with the present soil on top. 



Mancayan. — As you have suggested that the Mancayan region as shown 

 on the old Bureau of Mines topographic map might also be a remnant of 

 this old plateau, I studied it again, and I am in doubt about it. My opinion 

 is that the Mancayan Plateau is not to be correlated with these other plateau 

 remnants for the following reason: It seems to be an isolated topo- 

 graphic feature due to exceptionally hard quartz material, a part of which 

 is covered by a trachyte flow. Its topography seems to me to be quite 

 different from that of the other plateaus. 



Sagada. — It has been suggested by some that Sagada is another plateau 

 remnant. I have not visited this region since we have discussed this par- 

 ticular feature, but from my recollection of that country I am of the 

 opinion that it does not correspond to the areas we have been discussing. 

 There is a considerable bench near the Sagada Mission which is due to 

 subsidence. However, there may be other areas in the vicinity of Sagada 

 which I did not see. 



River terraces.—As one travels north on the Baguio-Bontoc Trail par- 

 ticularly in looking across Agno Valley to the east several well-defined 

 river terraces and elevated benches, at present far from the river, high 

 on the sides of the Polis Range are distinctly visible. These undoubtedly 

 are to be correlated with such terraces and benches as we have noted in 

 Bued River Canon near the Kias Trail and in the country to the northwest 

 of Trinidad. 



