PRELIMINARY REPORT. 21 
smaller and isolated islands as Tikei, Aki-Aki, Nukutavake, and Pinaki, as 
well as the Gloucester Islands, rise from greater depths and are isolated 
peaks. At any rate, these soundings indicate, as do the soundings off the 
- Fijis, that atolls do not necessarily rise from very great depths, and that 
in this characteristic atoll district, atolls are found, it is true, with steep 
slopes, but rising from moderate depths. The slopes of these atolls would 
probably resemble in every respect the slopes of the elevated coralliferous 
limestone islands characteristic of the Lau Group in Fiji, where they have 
not been obliterated by erosion, denudation, and atmospheric agencies. 
The deepest sounding among the Paumotus was on the line to thé 
northward of Hereheretue in the direction of Mehetia, where we found a 
depth of 2524 fathoms, and a continuation of the red clay characterizing 
the soundings since we left Pinaki. In nearly all the soundings among 
the Paumotus, even at moderate depths not far from the atolls, we 
brought up manganese particles or small manganese nodules. The last 
haul, made in deep water on the way from Hereheretue, in 2440 fathoms, 
on the way to Mehetia, brought at least half a ton of manganese nodules, 
the bottom being’ red clay. 
We steamed about 2500 miles among the Paumotus, and although 
we had not the advantage of the accurate surveys of the English Hydro. 
graphic charts, which made the exploration of Fiji so easy, yet from 
the structure of these atolls it was a comparatively simple task, by steam- 
ing around the islands and landing wherever practicable, to get a fairly 
good idea of their structure. We have seen nothing in this more ex- 
tended examination of the group tending to show that there has any- 
where been subsidence. On the contrary, the existing condition of the 
atolls of the Paumotus cannot, it seems to me, be explained on any 
other theory except that they have been formed in an area of elevation; 
an area of elevation extending from Matahiva on the west to Pinaki in 
the east, and from the Gloucester Islands on the south to Tikei on the 
north, although the islands in the line of Mangareva to Tahiti are sep- 
arated from the other Paumotus by a deep channel, nearly 200 miles 
wide and more than 2400 fathoms in depth, with scattered islets and 
atolls extending from Mangareva to Pinaki, and northward to Puka-ruha 
