Historic Littoral Cones- — M oore and Ault 
atmosphere in all directions was filled with ashes, 
spray, gasses, etc.; while the burning lava, as it fell 
into the water was shivered into millions of minute 
particles, and, being thrown back into the air fell in 
showers of sand on all the surrounding country. The 
coast was extended into the sea for a quarter of a 
mile, and a pretty sand beach, and a new cape were 
formed. Three hills of scoriae and sand were also 
formed in the sea, the lowest about two hundred, and 
the highest about three hundred feet. 
For three weeks this terrific river disgorged itself 
into the sea with little abatement. Multitudes of fish 
were killed, and the waters of the ocean were heated 
for twenty miles along the coast. The breadth of the 
stream, where it fell into the sea, is about half a mile, 
conforming itself, like a river, to the face of the 
country over which it flowed. 
Brigham states further (1909:54) that: 
The sand hills thrown up at this place were found 
to be one hundred and fifty, and two hundred and 
fifty feet high eight months after their formation, but 
since then the sea has removed the whole mass. Even 
in 1865 they were not a third of the measured height 
and nodules of olivine were abundant in the sands 
of the beaches at considerable distance. 
Most of the remnants of the 1840 cones are 
composed of rather thin-bedded glassy ash and 
lapilli. In the wave-cut cliff facing the sea, the 
bedded ash lies on top of lava which is probably 
from the same eruption. A second lava flow 
overlies the bedded lapilli on the north side of 
the larger cone remnant. This lava flow has 
baked and oxidized the littoral cone ash a few 
inches below it. The upper flow represents con- 
tinued movement of 1840 lava over the cone 
which was produced by the littoral explosions. 
The littoral cone ash is crudely bedded, rang- 
ing from material 1 or 2 mm in size down to 
abundant silt-size dust. The 1840 flank lava was 
quite picritic, with approximately 20% olivine; 
consequently many of the ash particles are whole 
or fractured olivine crystals. Much of the cone 
is composed of beds of glassy ash about 5 cm 
thick, interbedded with layers about 1 cm thick 
of slightly coarser material. The coarser material 
is similar but contains a higher percentage of 
the larger chunks of glassy cinder, many from 
Vi to 1 cm in diameter, and some as much as 
4 or 5 cm in diameter. 
These beds can be traced for a hundred feet 
or more. The coarser beds may have been formed 
during the more violent phases of the steam 
explosions, or they may represent periods of 
5 
wind gusts which momentarily blew away the 
finer material. 
1868 Cones 
The littoral cones produced in 1868 are 
located on the coast 4 miles northwest of Ka 
Lae, the south cape of the island ( Fig. 1 ) . The 
main feeding flow passes between two cones; 
the one on the northwest is now 118 ft high, 
and the one on the southeast, called Puu Hou 
(new hill), is more than 240 ft high and about 
1,500 ft in diameter at the base. A large part of 
Puu Hou has been eroded since its formation, 
and a substantial part has been removed since 
1924, judging by photographs taken at that time 
by Stearns (Fig. 2). 
The cones were formed by the lava flows 
from the Mauna Loa flank eruption at 2,500 ft 
altitude, which began April 7, 1868, and con- 
tinued for 15 days. Of the 190 million cubic 
yards of lava erupted, about 100 million cubic 
yards flowed into the sea (Stearns and Mac- 
donald, 1946:79). 
There are no detailed descriptions by eyewit- 
nesses of the actual formation of Puu Hou. 
However, Rev. Titus Coan, who visited the area 
in August, 5 months after the eruption, writes 
(Brigham, 1909:115): 
Since three miles from the head the main stream went 
altogether over the precipice, and pursued its rapid 
course over the pahoehoe some seven miles to the sea 
which it reached in two hours. There it formed, as is 
usual when lava streams enter the sea, two cones of 
lava sand, or lava shivered into millions of particles 
by coming in contact with water while in an intensely 
heated state. There is no island there and there is 
nothing but what is common under similar circum- 
stances. This stream is about half a mile wide, and it 
entered the sea some three-fourths of a mile from the 
big pali before spoken of. After running a day or two, 
in this channel, partial obstructions occurred, by cool- 
ing masses, when the shell of the stream was tapped 
some five miles from the sea, and a torrent of white- 
hot lava pushed out on the east side, running off to 
the great precipice and following its base in a breadth 
of half a mile down to the sea. . . . 
In general the cinders composing Puu Hou 
are coarser than those of the other littoral 
cones studied. The cinders are crudely bedded, 
the differences between beds being mainly slight 
differences in size and sorting of the fragments. 
Among the fine cinders and glassy ash are a 
