432 PACIFIC OCEAN. 
hensible subterranean force. The lifting of the continents may have 
been only a result on the whole of the deepening of the ocean’s bed.* 
The fractures attending contraction, would occasion earthquakes with- 
out the medium of vast cavities within the earth for the conveyance 
of vapour. ‘The abrupt yielding of the earth’s crust, after long ages 
of increasing tension, would cause vast agitations of the oceans, as 
well as changes of level; and epochs in the earth’s history might thus 
be marked off. 
It is a remarkable fact confirmatory of these views, that the axis of 
subsidence in the Pacific, as indicated by the coral islands, is very 
nearly identical with that which would be deduced from the positions 
of the ranges of islands. The author had previously laid down the 
former, and by an independent train of reasoning without connexion 
in the mind, arrived at almost the same position for the latter. The 
great central chain of islands, it is observed, curves with the convexity 
to the southwest. It seems like an outline of a vast elliptical area, 
or lke a concentric line across such an area. The Hawaiian chain 
on the north, has a slight curvature in the opposite direction. The 
former consists of subordinate parts that are “advancing”’ successively 
toward the northward, while in the latter the parts are “advancing” 
to the southward; that is, the two have a reverse relation to the in- 
cluded area, although the Hawaiian line is much more nearly straight. 
We therefore conclude with reason that the axis of greatest subsi- 
dence for the central part of the ocean should be drawn somewhere 
between these groups. A consideration of all the circumstances bear- 
ing upon the question have led us to place it on our chart along a 
course extending from near Easter Island, towards the north of 
Niphon (Japan). ‘This line (A’ B’) passes by the Marquesas and 
* Some of the effects of this cause are presented by C. Prevost in the Bulletin of the 
Geol. Soc. of France, xi. p. 183. See also American Journal of Science, ii. ser. ii. 178. 
The following authors have written more or less fully upon contraction as a dynamical 
cause in geology.—M. Corprer, Essai sur la Temperature de la Terre, 4to. pp. 84; read 
before the Academy of Science, June 4 and July 9 and 28, 1827. American Transla- 
tion, Amherst, 1828. 
Eure pe Beaumont, Recherches sur les Revolutions de la Surface du Globe, ib. 1829. 
De ta Becue, Researches in Theoretical Geology, 12mo, London, 1834. 
M. Lesianc, Bull. de la Soc. Geol. de France, xii. 137, 1841. 
W. W. Marner, American Journal of Science, xlix. 284, 1845. 
J. H. Larurop, ibid. xxxviil. 68, xxxix. 90. 
Cuarues Bassace, Proceedings Geol. Society of London, 1834. Quarterly Journal 
of the Geological Society, No. 10, May 1, 1847, p. 186. 
Preceding all these authors, Lersnrrz in his Protogea, §§ iv. vi. xxii. 
