348 Volcanic Eruptions on Hawaii. 
of amazement. The former rises with a scarcely per- 
ceptible inclination, (see annexed cut,) without a break 
in the surface appareut in the distant view ; then grad- 
ually rounds over, and declines on the opposite side 
with the same. gentle declivity. ‘The eye following 
along, up and down the sides of Mount Kea, meets 
with the same slopes, and only few traces of indenta- 
tions. Mount Loa is a flat dome.. Mount Kea rises 
to the same altitude, and differs only in having the 
summit somewhat pointed. 
From these descriptions the statement will be ap- 
preciated that the heights of Hawaii are not peaks in 
mountain range, but three isolated domes or lo 
PA 
cones, united by a confluence of lavas at base. ‘lhe = 
surface of the island is not a mass of broken moun- g 3 
tains, but the simple slopes of these elevations. Yet & 4 
on an actual scramble over the sides, there are found 5 = 
exteusive ravines and ridges of lava which impede the § 
progress; and numerous craters form large elevations * 
usually ranging between three and nine hundred feet in © 
height. There are also numerous gorges on the eastern & 
aud northern foot of Kea, which extend from the sea = 
half-way up the mountain, and are from three hundred = 
to a thousand feet in depth. The Kohala range on 2 
the north, which is the only part not conformable to * 
this system, faces the interior of the island with a E 
nearly vertical front, while northward the slopes are & 
less abrupt and are profoundly intersected by valleys. | 
Mount Kea has an average slope of 7° 46’. The % = 
slope of Mount Loa on the south averages 7° 33’; * 5 
on the west 5° 28’; on the east, to Kilauea, (a distance A. 
of 19°8 miles from the axis,) 6° 42’: making 6° 30’ cP 
the average for the dome. From Kilauea to the sea, 
the slope averages but 1°28’, equivalent to 135 feet 
tothe mile. The following map of a part of Hawaii* 
will assist in conveying an idea of the form of Mount 
Loa, the position of the crater at summit, and of Ki- 
lauiea on its east-southeastern flank, 3970 feet above 
he sea. 
We may hence assume 6° 30/ as the average incli- 
nation of the great dome. This gives for the base 
of the dome a breadth of forty-five and three-fourths 
miles. This however is only the central portion of 
the mountain: for the slopes spread very much below, 
sinnniviillnidinistnaiiicslog saan 
* This map is reduced from the chart published with the Narrative of the Expe- 
dition. 
