TOPOGRAPHY. 23 
westward the line becomes more northwest; and concurrently, if not 
consequently, the east side of the Feejee Group, lying near the Tongan, 
trends nearly the same with it, or N. 23° E.; while the west side, which 
is from 150 to 200 miles distant, trends N. 40° E., or nearly at right 
angles with the Vaitupu range on the north and New Hebrides on 
the south. The Feejee Group is therefore wedge-shape, like Borneo, 
with the narrow side of the wedge, however, in the opposite direction. 
d. 'The Ladrones, in their northern part, are parallel with Formosa 
and Luzon ; but the southern portion trends westerly, so as to be nearly 
at right angles with the Salomon range, or the southern east-and-west 
portion of Luzon, which line, we have stated, may possibly be con- 
tinued in the Pelews. 
e. It is of course impossible that the curving ranges should be uni- 
formly at right angles: the system exhibited is actually inconsistent 
with it. Thus the bending northward of the Samoan chain at the 
Marshall Islands, approximates it to a rectangularity with the western 
part of the Hawaiian range, but at the same time to a parallelism 
with the Ladrones. Yet we observe in this same region that the 
Carolines branch off westward, at right angles with the Ladrone 
range. ‘I'he same convergings and cross-courses are apparent in the 
East Indies. 
III. The parts of the ocean where the two systems correspond 
most nearly with the equatorial and meridional directions respec- 
tively, are those which abound most in lands. The Tongan, Samoan 
and Feejees constitute one of these regions. ‘The Hast Indies another. 
The West Indies and Mexican mountains are an example of a similar 
_ kind. 
With regard to the causes of the system of things pointed out, 
we offer nothing in this place, as our object has been simply to pre- 
sent the facts in illustration of the physical geography of the Pacific. 
Il. GENERAL CONSTITUTION OF THE PACIFIC ISLANDS. 
An area of the extent of the Pacitic might be expected to present 
some considerable variety in the geological constitution of its lands, 
at least as much as is observed among the loftier summits of the con- 
tinents. This is, however, far from the fact. Igneous rocks, volcanic 
or basaltic, and occasionally porphyritic, constitute all the islands of 
