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“The northern ridge extends from Cape Qnitang westward on the 
ridge leading to Buenavista Peak (altitude, 1,165 meters) ; from thence it 
follows the rim of the crater to Cabcaben Peak (altitude, 1,406 meters). 
The southern boundary is the ridge which starts at Cape Margahas and 
runs through Limay Peak to Caybubu Peak (altitude, 1,368 meters) and 
on the rim of the crater. The western and northwestern boundaries of 
the reserve are formed by lines vdiich descend from Cabcaben on the 
south and Caybubu on the north, meeting at the bottom of the crater, 
near the headwaters of the Balanga River.” 
“Between the north and south ridges are two main rivers — the Lainao 
and the Alangan. The Lamao River rises just south of the lowest point 
of the rim of the crater which connects Buenavista with Caybubu Peak. 
From its source down to within 3.5 kilometers of the shore it lies in 
a canon which varies in depth from 75 to 370 meters; below 3.5 kilo- 
meters the latter feature of the river disappears.” 
“The group of peaks known as Mount Mariveles is on the southern end 
of the peninsula of land comprising tire Province of Bataan, of the Island 
of Luzon. The meridian of 120° 30' east of Greenwich and the parallel 
of 14° 30' north latitude intersect the mountain near its summit. Rising 
to the height of approximately 1,400 meters, it, with the Island of 
Corregidor, is the most conspicuous feature of the landscape at the 
entrance of Manila Bay.” 
“The lithographic structure of Mount Mariveles shows it to be of 
volcanic origin. It is a mass composed largely of andesitic ejecta and of 
the decomposition products thereof. The physiographic features which, 
point to its being an extinct volcano are almost as striking. Rising from 
Manila Bay on the east, from the China Sea on the south and west, 
and from the lowlands near the central part of Bataan on the north, 
are a series of prominent ridges ending in peaks, which, with their 
connecting ridges, form a nearly circular chain — the rim of the former 
crater which has an outlet to the north, by way of the Balanga River. 
Between these peaks and just beneath the lowest point of the connecting 
ridges are the sources of the main rivers draining the mountain; the 
latter have cut deep canons and have established many branches with 
smaller ones.” 
The general vegetative conditions of the Lamao Forest Reserve are 
characteristic of large portions of the Philippines. From the coast, the 
land slopes gradually i;pward, reaching an elevation of about 100 meters 
at a distance of about 4.5 kilometers, where the sharper slopes of the 
mountain are encountered. This gently sloping plain region is covered 
with dense bamboo thickets and low, scrubby forests or thickets, consisting 
of numeror;s species of small trees and shrubs, with an intermixture of 
erect and scandent bamboo, vines, etc., and very few scattered large trees, 
while here and there are open, grassy parks of varying size. Occasionally 
one finds traces of cultivation and it is possible that much of this plain 
region has been cultivated at one time or another. At the distance from 
