J.D. Dana on Changes of Level in the Pacific Ocean. 161 
are basaltic islands of great magnitude. Again, along to the 
horth side of the Vanikoro Group, the Salomon Islands, and New 
teland, there are coral atolls, though scarcely one to the south. 
In view of this combination of evidence, we cannot doubt that 
the subsidence increased from the south to the northward or 
northeastward, and was greatest between the Samoan and Ha- 
Waiian Islands near the centre of the area destitute of islands, 
about longitude 170° to 175° W. and 8° to 10° N. 
Hawaiian Range.—We observe that the western islands in 
the Hawaiian Range, beyond Bird Island, are coral islands, and 
all indicate some participation in this subsidence. To the east- 
Ward in the range, Kauai and Oahu have only fringing reefs, yet 
mMsome places these reefs are half a mile to three-fourths in 
Width. ‘They indicate a long period since they began to grow, 
Which is borne out by the features of Kauai showing a long res- 
Pite from volcanic action. We consequently detect proof of but 
little subsidence of the islands. Moreover, there are no deep 
should, therefore, conclude that these islands lie near the limits 
of the subsiding area, and that the change of level was greatest 
Marquesas.—The arquesas are remarkable for their abrupt 
Shores, often inaccessible cliffs, and deep bays. The absence of 
sentle slopes along the shores, their angular features, abrupt sound- 
1 ar 
cut evidence that they participated in the subsidence of the 
a but not to the same extent. ‘They are nearly destitute of 
Gambier or Mangareva Group.—In the Southern limits of 
ihe Paumotu Archipelago, where, in accordance with the forego- 
ng Views, the least depression in that region should have taken 
Place, there are actually, as we have stated, two high islands, 
Piteairn’s and Gambier’s, There is evidence, however, in the 
