STRUCTURE OF OORAL ISLANDS. 203 
Manhii, Wilson’s or Waterlandt, Paumotu Archipelago, 
14° 25’ S., 146° W. 15 miles by 6, trending EK. N. EK. A 
large lagoon with a deep entrance on the west side. Shape 
oblong triangular. 
Shore platform as usual; mostly under water at low tide. 
Large masses of coral here and there, standing on this reef, 
either cemented to it, or loose. One top-shaped mass is figured 
on p.179. High water did not reach the part of it which was 
most worn ; and this was evidently owing to the fact that the 
action of the swell or waves is greatest above the actual level 
of the tide at the time. The reef-rock is either a compact 
limestone, showing no traces of its composite origin, or a con- 
glomerate. Beach, regular as usual, six to ten feet high, con- 
sisting of coral sand, and fragments of worn shells, with occa- 
sional exuvie of crabs, remains of Echini, fish, etc. The en- 
trance to the lagoon is deep and narrow, with vertical sides. 
Aratica or Carlshof, Paumotu Archipelago, 15° 30’S., 
145° 30’ W. 17 miles by 10, trending N. E: Large lagoon 
with a good entrance for vessels. The reef fronting south 
bare for nine miles; on northwest side, mostly very low, with 
only here and there a clump of trees; occasionally a line of 
wooded land for a quarter of a mile on the east side; more 
continuously wooded on the north. The bare parts mostly 
covered with blocks of coral, one to thirty cubic feet and larg- 
er, tumbled together as on the preceding. Some blocks of 
coral on the shore platform very large; one eight feet high 
and fifteen in diameter, containing at least 1,000 cubic feet. 
Nairsa or Dean’s, Paumotu Archipelago, 15° S., 148° W. 
44 miles by 17, trending W. N. W. Northern shore mostly 
wooded; southern with only an occasional islet, connected by 
long lines of bare reef. In these intervals, the reef stood 
eight feet or so out of water, according to estimate from ship- 
