216 HAWAIIAN ISLANDS. 
conjoint action of three volcanic cones, whose slopes constitute its 
surface. The ridge of Kohala on the north, which faces the inte- 
rior with vertical cliffs, and gradually declines on the opposite side, 
or towards the sea, is the only example of nonconformity to this 
system. As the place has not been geologically examined, we can- 
not give the exact character of this ridge, or its relations to the 
other parts of the island. Mount Kea was probably the earliest vent 
opened, if there was any difference of age. Its lavas long since ceased 
to flow, and the closing scene was an ejection of scoria—a common 
fact with many craters. Mount Hualalai and Mount Loa are still 
enlarging the territory of Hawai, by their occasional additions to its 
surface and shores. 
d. General Conclusions. 
We here continue our observations on the general character of vol- 
canic action on Hawaii. 
I. The absence of a cinder cone about the terminal crater of Mount 
Loa, or even of cinder ejections beyond a few small cones over some 
former fissure, is certainly a most striking feature, and one which 
should be well considered. We have a lofty volcanic mountain, 
finished off to its very top, and this top nearly 14,000 feet in elevation, 
without any appreciable addition at top from fragmentary erup- 
tions. Contrast this with the lofty summits of the Andes and Mexico. 
The consequence is that Mount Loa has the low flat shape described, 
and its terminal crater is but a pit in the broad top of the dome; 
while the peaks of the Andes rise with steep slopes, and a narrow 
summit often broken in by the convulsions of the volcano. 
Mount Kea is nearly as gentle in its average slope, though having 
a pointed summit from the character of the latest ejections; it is still 
very unlike a Chimborazo. 
II. The quietness of the eruptions merits farther remark. How 
totally unlike our usual conceptions of volcanic action, that a volcano 
of such magnitude, should pour out a flood of lavas, reaching for 
twenty-five miles down its sides, and yet all take place so quietly that 
persons at the foot of the mountain should be unaware of it, except 
from the glare of light after the action has begun ; and through its pro- 
gress should utter no sounds to be heard below, or cause perceptible 
vibrations, except in the region of the outbreak, and there none of much 
