46 USEFUL PLANTS OF GUAM. 



for a boat to stick upon the reef halfway between the ship and the 

 shore. There is a crooked channel through which boats of small size 

 may pass, and extensive dredging operations have been recommended 

 in order to enlarge the harbor and clear a channel from the harbor to 

 the shore, but the recommendations of the board have not yet been 

 carried out. a 



PHYSICAL GEOGRAPHY. 



Surface and contour. — From a distance the island appears flat 

 and even, but on approaching it the northern portion is seen to be a 

 raised platform or plateau (PI. I), with several low peaks rising from 

 it in the north, and to the southward a low, rounded hill, which has 

 received the vernacular name of "Tiyan" (belly). The southern half 

 of the island is mountainous. The island is irregular in shape. It 

 may be compared roughly to the shape of a human footprint (the 

 right foot), with the heel north-northeast and the toe south-southwest 

 (see map, PI. LXX). The general plane of the northern half is not 

 horizontal but shelving, with eastern and higher side bounded by 

 steep cliffs. The east coast of the southern half is penetrated by a 

 few small bays, none of which is capable of receiving a vessel. On 

 the west coast of the northern part of the island there are a number 

 of sand}^ bays fringed with coconut groves and separated from one 

 another by as many rocky points. 



The east shore is constantly beaten by a heavy sea caused by the 

 stiff trade winds which prevail during the greater part of the year. 

 The adjacent sea is very deep, so that it is impossible for vessels to 

 find anchorage there. The swell is even so great that it is dangerous 

 at most times for boats to attempt to enter the small ports in the 

 southern part, except at Hahahyan, at the extreme south, which is 

 sheltered from easterly and northeasterly winds. On the west side 

 of the island the sea is shallow enough in several places to permit 

 vessels to anchor within a safe distance of the shore, except during a 

 certain part of the summer, when winds from the southwest may be 

 expected. The favorite anchorage of the early navigators was the 

 roadstead of Umata (Humatag), where a good supply of fresh water 

 was always to be secured without difficulty. Afterwards the bay of 

 San Luis de Apra became used as a harbor, and is now the only port 

 of the island in which large ships can find anchorage. The little 

 harbor of Agana (Hagadna) can be entered only by vessels of the size 

 of launches, and the anchorage in Agana Bay is not considered safe. 



In Alexander Agassiz's description of the island h he gives a detailed 

 account of its shore line and the physical features of the island. The 



« See Report of the Guam Survey Board to the Secretary of the Navy, July 25, 1901. 

 6 The Coral Reefs of the Tropical Pacific, p. 366 et seq., 1903. 



