﻿148 SMITH. 



The sky line of the corclillera to the south is ragged and jagged, several 

 peaks standing between 4,000 and 7,000 feet above sea level. It is this 

 great watershed which causes the seasons to be so regularly and sharply 

 defined in this region. 



The plains. — Ilocos Norte is fortunately blessed with a fair extent 

 of coastal plain, particularly in its southern part; this varies from 1 

 to 10 miles in width and is very irregular, for spurs and offshoots from 

 the main mountain mass, in places, run well down to the sea. At about 

 5 miles from the sea one comes out upon the uplands, and at 17 miles 

 the really high mountains begin; Monte Cayudungan lies just about 

 that distance east of Sinait and it reaches an elevation of 4,81 G feet 

 according to Coast and Geodetic tri angulation. This plain, as one must 

 reasonably infer from the raised coral reefs along its border, consists of 

 a foundation of extremely recent coral formation overspread by a blanket 

 of silt largely derived from the mountains in the rear; I believe the 

 sediments of this to be to a great extent pluvial; that is, of flood-plain 

 origin and to be piedmont 1 deposits, especially where the distance from 

 the foot of the mountains to the sea is considerable; while just bordering 

 upon the littoral they are eolian, there being considerable dune formation 

 along this strip. In this connection I should make mention of the 

 recent articles by Professor Barrel 1 - who has emphasized the importance 

 of subaerial and pluvial sedimentation in the geologic record. In the 

 Tropics where we have high mountains and tremendous rainfalls, the 

 conditions are very favorable for the formation of this class of deposits 

 which are very fertile and possess a stiff substratum of clay which is so 

 necessary for rice culture. The Ilocanos inhabit this plain, whereas the 

 Apayaos (Tingians) are confined to the back country. This coastal 

 strip ends near the barrio of Dirique. Prom there on, around the north 

 coast, there is every indication of very recent vulcanism; in fact, from 

 Bojeador Light running eastward for some miles there occurs a long, 

 black, rugged, treeless ridge of "eruptive conglomerate" which appears 

 to be more recent and quite apart from the rest of the country. 



The uplands. — The upland country is not a continuous tract, but is 

 constituted of a series of very irregularly shaped plateaus which ap- 

 proximate 2,000 feet in elevation. These are partly underlain by lime- 

 stone, partly by dolerite (f. n.) ; in the former case they are rolling and 

 grassy, in the latter they have more relief and are barren and treeless. 

 Plate III, fig. 2, and Plate IV, fig. 3, will give some idea of this country. 

 The ascent to these higher levels is quite difficult, but the traveler is 



'Barrell, Jos.: Geological Importance of Sedimentation. Jour, of Geol., U. of 

 O. (1906), 14, 328. 

 2 Ibid. 



