SAMOAN ISLANDS. 309 
In our remarks on the Samoan Group, we commence with those to 
the eastward. 
I. MANUA, OFU, OLOSENGA, AND ROSE ISLANDS. 
The island of Manua is described as having the form of a regular 
dome.* The sea is bordered in most parts by a cliff of three or four 
hundred feet, above which the ascent is gentle and comparatively 
even. Along the shores, layers of conglomerate were observed con- 
sisting of coarse fragments of the basaltic rock often as large as the 
head. ‘The stratification in the cliffs was distinct, and appeared to 
be horizontal, although in some places much undulated, and at times 
contorted.” 
Ofu and Olosenga form a narrow line of land divided into the two 
parts which constitute the separate islands merely by a boat channel 
a fourth of a mile wide. ‘They were apparently once united. 
Olosenga has bold precipitous shores and is three miles in length. 
Ofu is similar in its features, but smaller, the length not exceeding 
three-fourths of a mile. 
Rose Island is a low coral atoll. Masses of basalt were observed in 
one or two places on its reefs, which had probably been carried there 
by floating logs, or as the ballast of some canoe. 
DSS LAIN D Om UT U TA: 
Tutuila, in the distant view, is less varied in its outline and less 
lofty in its mountain heights than the islands of the Society Group.t 
The highest summit, Matafoa, according to observations with a 
sympiesometer by Mr. Couthouy, is 2327 feet in height. Its surface 
presents the same general features as Tahiti, though on an inferior 
scale. The ridges are precipitous, often rising with mural fronts, and 
thinning out above to a sharp trenchant edge. A few serrated sum- 
mits and needle peaks are interspersed among the tamer heights, and 
distinctly indicate by their features the geological structure of the 
* See Narrative, ii. 65. 
t We came to anchor at Tutuila late on Friday, and by Saturday noon all hands were 
ordered aboard to sail for Upolu. A single ramble of four hours and a half was, there- 
fore, all the opportunity I had for examining the island, 
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