840 
istic of the elevated reefs of Fiji, and which, 
from the evidence of the fossils and the 
character of the rock, both Mr. Dall and 
myself have been led to regard as of terti- 
ary age. 
As we approached the island from the 
northwest it soon became evident that it 
presented all the characteristics to which I 
had become so accustomed in Fiji, and, 
upon landing, this was found to be the case. 
The cliffs had the same appearance as those 
of Vatu Leile, Ongea, Mango, Kambara, 
and many other elevated islands of Fiji. 
There were fewer fossils perhaps, but other- 
wise the petrographic character of the rock 
was identical with that of Fiji. Mr. Meyer 
collected upon the top of the second terrace 
a number of fossils similar in all respects to 
those we found in the Fiji elevated corallif- 
erous limestones. 
The southwestern extremity of the island 
‘sloped gradually to the sea and showed two 
well-defined terraces. The lines of these 
two terraces could, as a rule, be traced 
along the faces of the vertical cliffs by the 
presence of caverns along the lines of those 
levels, similar to the line of caverns indi- 
cating the line of present action of the sea 
at the base of the cliffs. As we steamed 
around the island there were distinct indi- 
cations of two additional terraces on the 
line of the vertical cliffs on the weather 
side of the island. The position of these 
terraces was usually more clearly seen along 
the face of the cliffs at prominent points 
where they were undercut much as I have 
figured them for certain cliffs in Vatu Leile, 
in Fiji, in my report on the islands and coral 
reefs of that group. 
Of course it is premature from this ex- 
amination of the western extremity of the 
Paumotus to base any general conclusions 
regarding the mode of formation of these 
atolls ; certainly as far as I have gone there 
is absolutely nothing to show that the atolls 
of the Paumotus have not been formed in 
SCIENCE. 
[N.S. Vou. X. No. 258. 
an area of elevation similar to that of Fiji. 
The evidence in Rairoa and in the atolls of 
the western Paumotus is very definite. 
Makatea is an elevated mass of coralliferous 
limestone similar in all respects to masses 
like Vatu Vara, Thithia, and others in 
Fiji. Like them Makatea is surrounded by 
a comparatively narrow shore platform cut 
out from the base of the limestone cliffs 
and on the seaward extension of which 
corals grow abundantly to depths of 7 to 
8 fathoms, when they appear to become 
very much less numerous. So that it is 
not unnatural, as I am inclined to do, to 
look upon the area of the Paumotus as one 
of elevation, the raised and elevated land 
of which has been affected much in the 
same way by denudation and erosion as 
have the masses of elevated coralliferous 
limestone of Fiji. Only there seems to 
have been, from the evidence thus far pre- 
sented, a far greater uniformity in the 
height of the elevation of the Paumotus. 
This would render the explanation I have 
given less evident had I not the experience 
of the Fiji group to guide me. I am in- 
formed that there are other islands and 
atolls in the Paumotu group, showing 
traces of this elevation, so that Iam at any 
rate justified in denying that the Paumotus 
as such are situated in an area of subsi- 
dence and that subsidence has been the 
great factor, as is maintained by Darwin 
and Dana, in the formation of the charac- 
teristic atolls of the group. 
It may be well to point out also that the 
Paumotus, like the Marquesas on one side 
and the Society Islands on the other, are 
situated upon a plateau similar to that 
upon which the last mentioned groups are 
placed—this plateau having a depth of 
from 1200 to 1500 fathoms and rising from 
the general oceanic basin which surrounds 
them and which has a depth of from 2300 
to 2500 fathoms. Furthermore, evidence of 
this elevation is found at the two extremi- 
