48 USEFUL PLANTS OF GUAM. 
siz describes as ‘a volcanic massif which has burst through the coral- 
liferous limestone,” and which at Mount Tengho reaches to a height 
of more than a thousand feet. The volcanic range to which it belongs 
has burst through the limestone near Agafia and extends southward, 
parallel to the west coast, at a distance of about 1 or 2 miles from the 
shore. Its highest peak, called Humuyong-manglo (‘* Source-of-the- 
wind”), back of Umata, reaches a height of 8390 meters. Considerable 
denudation has already taken place on the volcanic slopes, forming in 
the interior of the island a number of peaks, ridges, and pinnacles. 
On the western and southern sides of the volcanic mountains the lime- 
stone masses which once covered their sides have in great measure dis- 
appeared through disintegration, and the soft material covering the 
slopes is constantly being washed down their sides. Many of the val- 
leys form small canyons with very steep walls. 
The peninsula of Orote and Apap Island are composed of elevated 
coralliferous limestone containing well-preserved fossils. These show 
no signs of metamorphism, as do those collected in the immediate 
vicinity of Mount Makahnag, where the limestone comes into contact 
with volcanic rock. The fossils are, however, highly calcified, and 
their hardness and the crystallization of the rocks would seem to indi- 
cate considerable age. 
THE HARBOR.—The bay of San Luis de Apré is the only harbor for 
vessels. It is protected on the southwest by the promontory of Orote, 
on the east by the island of Guam itself, on the north by Apapa island 
and the adjoining reef of Luminan, which is awash at high water. 
From this reef a bank (Kallang) extends to the southwestward toward 
Orote Point, terminating in two rocks which rise to within a few feet 
of the surface, leaving a narrow but deep channel, which serves as an 
entrance to the harbor. Apapé island consists entirely of elevated cor- 
aulliferous limestone deeply pitted and honeycombed. The limestone 
mass is full of crevices, potholes, and funnels, covered with stalactites. 
The island does not rise more than 8 or 10 feet above high-water mark. 
The shore is undercut and the island furrowed by numerous gullies; 
it is full of caverns, crevices, and pits.¢ 
As the harbor is much obstructed by coral reefs and is at a consid- 
erable distance from the seat of government of the island, a board of 
officers was sent to make a survey of it, with a view to its improve- 
ment, either by dredging or the construction of a breakwater along 
the reef, or both. It is intended to make it the site of a naval base 
and coaling depot of large capacity, as well as to serve as a commercial 
port. The board was directed to make recommendations as to the 
removal of reefs and other obstructions to navigation; to draw up 
plans for wharves, docks, storehouses, barr acks, hospital, water sup- 
a See Agassiz, Oop. cit. ., p. 370, 
