SUBSIDENCE IN PACIFIC CORAL REGIONS. 363 
where, evidence of comparatively recent eruption; from it, 
therefore, we gather no certain facts bearing on this subject. 
East of Tutuila is the coral island, Rose. It may be, there- 
fore, that the greatest subsidence in the group was at its 
eastern extremity. 
Feeee Islands. — We have already remarked upon the 
change of level in this group. A large amount of subsidence 
is indicated by the extensive reefs in every portion of the 
group, but it was greatest beyond doubt, in the northeastern 
part. The subsidence, where least, could hardly have been 
less than 2,000 to 5,000 feet. 
We have thus followed around the borders of the coral 
area; and, besides proving the reality of the limits, have 
ascertained some facts with reference to a gradual diminu- 
tion of the subsidence toward, and beyond, these limits. A 
Ine through the Hawaiian Group would pass along the 
northern boundary line of the area; and, taking the southern 
boundary as given on page 357, the oblong area narrows 
eastward. An axis nearly bisecting this space, drawn from 
the eastern Paumotus toward Japan, passes through the re- 
gion of greatest subsidence, as above determined and now 
proved by soundings, and may be considered the line of great- 
est depression for the area of subsidence. 
It is worthy of special note, that this axial line, or line 
of greatest depression, coincides in direction with the mean 
trend of the great ranges of islands, it having the course, N. 
56° W.; and it also corresponds approximately with the 
axial line of the Pacific Ocean. On the map of the Phoenix 
Group, Plate XI, the axial line is drawn just as it was laid 
down in the author’s Expedition Report. Moreover, this map 
gives the soundings that have been recently made in the seas, 
and it is interesting to find full confirmation of the conclu- 


