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 th rough 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 
rarried out.@ 
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 (Pl. 1), 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, Pl. 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 sandy 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 north easterly 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 (Humitag), 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 Agaiia (Hagadiia) can be entered only by vessels of the size 
of launches, and the anchorage in Agafia Bay is not considered safe. 
In Alexander Agassiz’s description of the island? 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. 
’The Coral Reefs of the Tropical Pacific, p. 366 et seq., 1903. 
