CHANGES OF LEVEL. : 397 
long period since they begun to grow, which is borne out by the 
features of Kauai showing a long respite from volcanic action. We 
consequently detect proof of but little subsidence of the islands. 
Moreover, there are no deep bays; and, besides, Kauai has a gently 
sloping coast plain of great extent, with a steep shore acclivity of one 
to three hundred feet, all tending to prove the smallness of the subsi- 
dence. We should, therefore, conclude that these islands lie near the 
limits of the subsiding area, and that.the change of level was greatest 
at the western extremity of the range. 
Marquesas.—T he Marquesas are remarkable for their abrupt shores, 
often inaccessible cliffs, and deep bays. The absence of gentle slopes 
a.ong the shores, their angular features, abrupt soundings close along- 
side the islands, and deep bays, all bear evidence of subsidence to some 
extent ; for their features are very similar to those which Kauai or T’a- 
hiti would present if buried half their height in the sea, so as to leave 
only the sharper ridges and peaks out of water. ‘They are situated 
but five degrees north of the Paumotus, where eighty islands or more 
have disappeared, including one of at least fifty miles in length. There 
is sufficient evidence that they participated in the subsidence of the 
latter, but not to the same extent. ‘They are nearly destitute of coral. 
Gambier or Mangareva Group.—In the southern limits of the Pau- 
motu Archipelago, where, in accordance with the foregoing views, the 
least depression in that region should have taken place, there are 
actually, as we have stated, two high islands, Petcairn’s and Gam- 
bier’s. There is evidence, however, in the extensive barrier about 
Gambier’s (see cut on page 130), that this subsidence, although less 
than farther north, was by no means of small amount. On page 
47, we have estimated it at 1150 feet. ‘These islands, therefore, 
although towards the limits of the subsiding area, were still far 
within it. The bays of the Mangareva Islets are of great depth, and 
afford additional evidence of the subsidence. 
Tahitian Islands.—The Tahitian Islands, along with Samoa and 
the Feejees, are near the southern limits of the area pointed out. 
Twenty-five miles north of Tahiti, within sight from its peaks, lies 
the coral island Tetuaroa, a register of subsidence. Tahiti itself, by 
its barrier reefs, gives evidence of the same kind of change ; amount- 
ing, however, as we have estimated, to a depression of but two hun- 
dred and fifty or three hundred feet. The northwestern islands of the 
group lie more within the coral area, and correspondingly, they have 
100 
