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EVELAND. 



Oregon (United States) ranges and is true of other parts of the Great 

 Basin region of the United States, nor docs it represent the folded type 

 of which the Alps arc the most familiar example; huge folds and 

 overturns of strata like crumplings of so much paper. The strata 

 covering the cast and west flanks of the Philippine mountain areas have 

 been gently raised and broken, leaving the ends of the arch on cither 

 side, but a part of this tilting was due to the formation of the sea 

 deposits on the already inclined floor of the mass where the ridge has 

 been produced; moreover there has only been comparatively gentle 

 arching. 



PHYSIOGRAPHIC DISTRICTS. 



Beginning with a small region which locally represents such a simple 

 type of elevated country, there is developed within it four distinct phys- 

 iographic types : 



(1) The mountain region. 



(2) The elevated plateau. 



(3) The intermediate uplands. 



(4) The incised-valley system. 



THE MOUNTAIN REGION. 



The mountain region is barely represented. The eminence of Pakdal 

 is a remnant, no doubt, of the original ridge which ran north at an 

 elevation of probably over 6,000 feet, to join the higher region' of north- 

 ern Benguet. It stands up from the eastern edge of the Baguio Plateau 

 to a height of about 5,500 feet, and though seen from the west its eleva- 

 tion is not particularly noteworthy, the absence of the plateau on the 

 east reveals the height of this region in the drop-off to the valley of the 

 Antamok Eiver and in the unobstructed view of the Agno Valley and 

 the main Cordillera to the east from the top of the ridge. 



Mount Santo Tomas on the other hand is a part of the "mountain 

 region," but it is so only because of its height. It is not, as is Pakdal, a 

 remnant of the former configuration. Santo Tomas is a block mountain 

 of the faulted type and it is locally developed, being the only instance 

 of such development in the Baguio district. A fault scarp of about 

 1,500 feet marks the northeastern slope, which is closer to a vertical than 

 to a horizontal plane. The tilting of this large block of sedimentaries 

 is plainly to be seen from the Bued Eiver side of the Baguio Plateau 

 and the corner of the block — the crest of Santo Tomas — at 7,342 feet 

 above sea level, is as sharply defined as it could be pictured. Because 

 Santo Tomas is on the edge of the plateau the height is more apparent 

 from the south and west, where the slopes of the mountain run down 

 to the coastal plain. From the plateau side, where there is a difference 

 of elevation of less than 2,500 feet, this height is not as noticeable. 



