288 
MERRILL AND MERRITT. 
the country, from a geologic standpoint, has been more or less uneventful. 
No indications of glaciation have been found, so that we may infer that 
the climatic conditions have been essentially the same since the beginning 
of the Tertiary, or since these Islands emerged from the sea. 
From this region the Agno Eiver flows southward through a deep and 
narrow valley until it reaches the plain of Pangasinan, where it spreads 
out, turns to the west and north, and flows into Lingayen Gulf. The 
Abra Eiver drains the west-central part of the region, flowing generally 
in a westerly direction and emptying into the China Sea at Yigan. The 
northern and northwestern parts are drained by smaller streams, while 
the eastern portions are drained by the tributaries of the Cagayan 
Eiver. This stream is the longest and largest in Luzon, flows northward 
and empties into the China Sea at Aparri, on the north coast of the island. 
Between these main river systems is found the central cordillera of 
Luzon, the culminating peak of which is the high mountain known to all 
the local inhabitants, at least to those on the Benguet side, as Mount 
Pulog, or Pulag, as it is sometimes pronounced. It is situated in the 
northeastern part of Benguet subprovince, on the boundary between that 
subprovince and Nueva Vizcaya. 
The government of this region is at present organized into what is 
known as .the Mountain Province, comprised of several subprovinces, 
some of which, like Benguet, have approximately the sahie geographical 
limits as defined on the Spanish maps o'f the region, while the boundaries 
of others have been more or less changed. The entire region is for the 
most part inhabited by non-Christian aborigines, subdivided into numerous 
tribes, each tribe speaking a different language or dialect. The Mountain 
Province comprises what is defined on the Spanish maps as Benguet, 
Lepanto, Bontoc, Abra, and parts of Nueva Vizcaya, as well as portions 
of other of the neighboring provinces. The physical characteristics and 
the flora of the greater part of this area are for most part quite uniform. 
In the present paper, for convenience, the area under discussion is des- 
ignated under the collective name Benguet-Lepanto region. 
Mount Pulog, undoubtedly the highe'st peak in Luzon, and ranking in 
altitude next to Mount Apo, of southeastern Mindanao, among Philippine 
mountains, is situated at about 60 kilometers from the coast, on the 
central range, its approximate position being latitude N. 16° 30' 36" and 
longitude E. 120° 50' 20". The name and position of the mountain does 
not appear on any published map of the Philippines that we have been 
able to examine, and although it is by far the most prominent peak in 
the entire region, it seems to have been overlooked by the earlier ex- 
plorers. There are several reasons why the mountain so long escaped 
attention, one of the chief being that it is apparently in no place visible 
from the coastal plain of noxthern Luzon, on account of the high interven- 
ing coast range. Under favorable weather conditions it is probable that 
