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378 
a water frontage on Manila Bay of nearly 5 kilometers, extending from 
Cape Magarhas on the south, in a northerly direction, to Cape Quitang. 
These two points mark the lower ends of the main ridges which respec- 
tively are the northern and southern boundaries of the Reserve. 
The northern ridge extends from Cape Quiling westward on the ridge leading 
to Buenavista Peak (altitude, 1,165 meters); from thence it follows the rim 
of the crater to Cabeaben Peak (altitude, 1,406 meters). (Pl. 1.) The southern 
boundary is the ridge which starts at Cape Margahas and runs through Limay 
Peak to Caybubu Peak (Pl. II) (altitude, 1,386 meters) and on the rim of the 
crater. The western and northwestern boundaries of the reserve are formed by 
lines which descend from Cabeaben on the. south and Caybubu on the north, 
meeting at the bottom of the crater near the head waters of the Balanga River. 
Between the north and south ridges are two main rivers—the Lamao and the 
Alangan. The Lamao River rises just beneath the lowest point of the rim of 
the erater which connects Buenavista (Pl. Il) with Caybubu Peak. From its 
source down to within 3.5 kilometers of the shore, it lies in a caiion which varies 
in depth from 75 to 270 meters; below 3.5 kilometers the latter feature of the 
river disappears. Throughout its length it is an eroding stream, with alternating 
cascades and pools; near its source waterfalls of 15-20 meters and perpendicular 
walls 30 to 40 meters in height are prominent features; the breadth of the 
river at no place exceeds 12 meters. Four main branches, a number of wet- 
weather streams, and numerous ravines cut the slopes of the cafion of the main 
stream into many steep and shorter ridges and cafions; some of the details of 
this topography are shown by Plate Il. The cafon feature of the Alangan, 
although not so pronounced as that of the Lamao River, is still marked. It has 
not been successful in working its way to the rim of the crater; indeed, the 
Camayuan River, a branch of the Lamao, has its head waters above that of the 
Alangan and collects drainage which would otherwise be diverted to it. Thus 
the drainage territory has been divided between two rivers and this fact has 
prevented either one from obtaining a sufficient supply of water so as to make 
cafions as deep as would one river, draining the same territory, and as a conse- 
quence the topography is not as deeply dissected as it otherwise would be. The 
cone-like contour of Mount Mariveles is slightly disturbed by Limay Peak, the 
altitude of which is 978 meters. It may either be a more resistant portion of 
the ridge leading from Cape Margahas to Caybubu Peak, or a portion of a rim: 
of a smaller crater. The region to the north of it was not investigated with 
sufficient care to determine its true nature. 
Between the Lamao and Alangan Rivers the lower third of the reserve is 
drained by branches of both, by the short Ayam River, and by many ravines 
and wet-weather streams which have their outlets in the indentations of the 
shore line. These dissect the gently sloping, low plateau at the base of the 
mountain into a number of low ridges and shallow depressions. 
THE CLIMATE AND ITS INFLUENCE ON THE VEGETATION. 
The classification of the vegetation used in this paper is based upon 
its character, and the climatic differences of the region. ‘The climatic 
records for Lamao given below were gathered during a portion of my 
residence at that place; of themselves they are of little or no value, but 
comparatively, their usefulness in explaining some of the more marked 
