J. D. Dana on Changes of Level in the Pacific Ocean. 169 
with cocoanut trees. This unusual size for an island without a 
lagoon: indicates an elevation, which the height of the island, 
estimated at twelve feet, confirms. The elevation may have 
been tio or three feet. 
Palmyra Island, just northwest of Washington, is described 
by Fanning as having two lagoons; the westernmost contains 
twenty fathoms water. Fanning’s Island, to the southeast of 
Washington, is de&cribed by the same voyager as lower than that 
island. The accounts give no evidence of elevation. 
Christmas Island, still farther to the southeast, according to 
the description of Cook, its discoverer, had the rim of Jand in 
some parts three miles wide. He mentions narrow ridges lyin 
parallel with the sea-coast, which “must have been thrown up 
y the sea, though it does not reach within a mile of some o 
these places.” The proof of a small elevation is decided, but its 
amount cannot be determined from the description. The ac- 
count of EF. D. Bennett, (Geographical Jour., vii, 226,) represents 
tas a low coral island. : 
_ Sarvis Island, as seen from the Peacock, appeared to be eigh- 
teen or twenty feet in height, which, if not exaggerated by re- 
fraction, (we think it not probable,) would show an elevation of 
xX oneight feet. This island isa sand flat, with little vegetation, 
and is but two hundred miles south of Christmas Island. ; 
“4aiden, two hundred and fifty miles sontheast of Jarvis, near 
latitude 4° g, and jongitude 155° W., visited by Lord Byron, is 
scribed as not over forty feet high; but this may be the whole 
height, including the height of the trees. 
& Longa Islands and others in their vicinily. 
All the islands of the Tonga group about which there are reefs, 
Blve evidence of elevation: Tongaiabu and the Hapai islands 
Ist solely of coral, aid are elevated atolls. 
Bua, at the south extremity of the line, has an undulated, 
ek y surface, in some parts eight hundred feet in height. 
as was seen by us from shipboard, there is 
au elevated layer of coral reef-rock, twenty feet thick, worn 
Ot into caverns and with many spout-holes. Between the 
Sonthern shores sed the highest part of the island, we observed 
; '€ distinct terraces. Coral is said to occur at a height of three 
bu Gred feet. From the appearance of the land, we judged that 
the interior was basaltic; but nothing positive was ascertained 
M0 regard to it, | oh 
*%gaiabu (an island visited by us) lies near Ena, and is in 
some parts fifty or sixty feet high, though in general but twenty 
feet. fy has a shallow lagoon, into which there are two entrances ; 
ummocks of coral reef-rock stand eight feet out of water. 
at tka and most of the Hapaii cluster, are stated by Cook 
have abrupt limestone shores, ten to twenty feet in height. 
