•48 USEFUL PLANTS OF GUAM. 



siz describes as " a volcanic massif which has burst through the coi-al- 

 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 Agana 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 390 meters. Considei"able 

 denudation has already taken place on the volcanic slopes, forming in 

 the interior of the island a nimiber 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 Apapa Island are composed of elevated 

 corallif erous 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 Apra 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 ApapS, island 

 and the adjoining reef of Luminan, which is awash at high water. 

 From this reef a bank (Kalalang) 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. Apapa island consists entirely of elevated cor- 

 alliferous 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 

 oflBcers 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, barracks, hospital, water sup- 



oSee Agassiz, op. cit., p. 370. 



