406 PACIFIC OCEAN. 
think it not probable,) would show an elevation of six or eight feet. 
This island is a sand flat, with little vegetation, and is but two hun- 
dred miles south of Christmas Island. 
Malden, two hundred and fifty miles southeast of Jarvis, in latitude 
4° S. and longitude 155° W., visited by Lord Byron, is described as 
not over forty feet high; but this may be the whole height, including 
the height of the trees. 
Tonea Istanps and others in their vicinity. 
All the islands of the 'Tonga group about which there are reefs, give 
evidence of elevation. Tongatabu and the Hapaz Islands consist solely 
of coral, and are elevated atolls. 
Hua, at the south extremity of the line, has an undulated, mostly 
grassy surface, and is in some parts eight hundred feet in height. 
Around the shores, as was seen by us from shipboard, there appeared to 
be an elevated layer of coral reef rock, twenty feet thick, worn out into 
caverns, and with many spout-holes. Between the southern shores 
and the highest part of the island, I observed three distinct terraces. 
Coral is said to occur at a height of three hundred feet. From the 
appearance of the land, we judged that the interior was basaltic ; 
but nothing positive was ascertained with regard to it. 
Tongatabu lies near Eua, and is in some parts fifty or sixty feet 
high, though in general but twenty feet. It has a shallow lagoon, into 
which there are two entrances. Some hummocks of coral were ob- 
served by the writer standing eight feet out of water. 
Namuka and most of the Hapai cluster, are stated by Cook to have 
abrupt limestone shores, ten to twenty feet in height. Namuka has a 
lagoon or salt lake at centre one and a half miles broad; and there is 
a coral rock in one part twenty-five feet high.* 
Vavau, the northern of the group, according to Williams, is a 
cluster of elevated islands of coral limestone, thirty to one hundred 
feet in height, having precipitous cliffs, with many excavations along 
the coast. 
Pylstaart’s Island, south of Tongatabu, is a small rocky islet without 
coral. T'afuaand Proby are volcanic cones, and the former is still active. 
Savage Island, a little to the east of the ‘Tonga Group, resembles 
Vayvau in its coral constitution and cavernous cliffs. It is elevated 
one hundred feet.t 
* Cook’s Voyage.—Williams, p. 296. + Williams, p. 427. 
t Williams, p. 275, 276. Foster estimates the height at fifty feet, and speaks of a 
depression about the centre. 
