August 26, 1886] 
NATURE 391 
points were seen to give off steam from flattened conical 
heaps of dark-coloured @éb77zs, and at intervals these vents 
threw off large volumes of steam and vapour, darkened 
to a reddish hue by solid matters, which were discharged 
to a height estimated at from 200 feet to 500 feet. Four 
days later, when viewed from the eastward, the same 
range showed a similar appearance, allowing for the 
change in direction; but the cone on the summit of 
Ruawahia had evidently accumulated with greater rapidity 
than the others, and had acquired lateral cones, giving 
its outline a similar appearance to that of Rangitoto, 
near Auckland. 
“ During two clear nights I watched the eruption from 
these vents, and could distinguish them against the sky 
with a powerful binocular telescope ; but I never observed 
any illumination of the ascending steam clouds, as if 
from the surface of an incandescent mass within the vent, 
nor was there any sign of any outpouring of lava, either 
from these vents or from cracks or fissures in the sides of 
the mountain, during the time of my visit. In addition 
to the above-mentioned conical vents on the summit of 
the range, along its eastern side the line of fissure already 
alluded to was distinctly visible, emitting wreaths of 
steam. This line of fissure lay in an oblique direction, 
so that it appeared to gain in elevation along the sides of 
the mountain from north towards south, but not suffi- 
ciently so as to indicate for it a direction that would make 
it continuous with the great fissure south of Tarawera, 
but rather in the direction of line AC on plan. It is 
below this fissure-line on the eastern flank of the range 
that bulky terrace-like accumulations of pumice-sand have 
been formed, and if this eruption should ever reach the 
stage of producing lava, which from other circum- 
stances I think hardly likely, it is from this fissure that I 
should expect the lava to exude. 
“III. The Great Fissure—This is the most remarkable 
and characteristic feature of the late eruption, and the 
chief origin of the disastrous results which attended it 
(B D on plan). A good view, but much obscured by 
steam, was obtained from the hill called Te Hape-o-Toroa 
—alt. 2300 feet—by Mr. Park on the 14th, and by myself 
on the following day. This fissure seems to commence as 
a narrow rift at the northern end from the great rent 
which has been formed in the south end of Tarawera 
Mountain. ‘This rent is a most wonderful feature. It is 
not a slip from the mountain side, but appears as if a 
portion of the mountain measuring 2000 feet by 500 feet, 
and 300 feet deep, had been blown out, leaving a ragged, 
rocky chasm, from which steam was being discharged in 
rapidly-succeeding puffs. The eastern side of this chasm 
was brightly tinted, as if by the efflorescent deposit of 
a mineral substance, probably ferrochlorides. Sulphur 
has been mentioned as a deposit from this recent outburst 
by some who have witnessed it; but this is hardly a 
possible result of such rapid volcanic developments. 
“ The view I obtained of the extent of this chasm south 
was much obscured by numerous volumes of steam blow- 
ing off from the newly-formed fumaroles that occupied 
the site of Rotomahana. From the eastern slope of Te 
Hape-o-Toroa we looked right into the fissure, and, as 
far as I could see, it appeared to have a nearly straight 
boundary of undisturbed ground on its eastern side, 
extending from the Tarawera chasm to within a few 
chains of Lake Ckaro, thus intersecting the Rotoma- 
kariri or the cold lake, the Rotomahana Lake, and the 
valley extending from thence southward. The west side 
of the fissure, on the other hand, is very irregular in 
outline, and is continually being altered by the falling-in 
of its precipitous walls, as the hills are undermined by 
the action of powerful geysers, seven in number, which at 
irregular intervals throw up great volumes of boiling 
water, with stones and mud, to a height of 600 feet to 
800 feet from the bottom. 
the steam that any idea can be formed of the nature of 
the bottom of this huge fissure ; but it seemed as if it was 
entirely occupied by large circular areas of mud, seething 
and boiling in such a fashion as to convey the impression 
of its being in a very liquid state. These mud-pools are 
separated from one another by comparatively solid ground, 
and in some cases, especially towards the eastern side of 
the fissure, what appear to be small pools of water with 
sedgy margins could even be distinguished; but the 
difficulty of estimating distances and depths through 
the steam-clouds rendered the observations made very 
uncertain. 
“ The largest of these mud geysers appeared to be that 
rising from the position formerly occupied by the Pink 
Terrace, but the most interesting is one a mile further 
south, which, unlike the others, does not spring from the 
bottom, but from the comparatively high ground on the 
west side of the fissure, and, owing to the obliquity with 
which the fragments are thrown out, is gradually building 
up a conical mound, which already has attained an alti- 
tude of several hundred feet (Mount Haszard, on plan). 
At the southern extremity the fissure is bounded by a bold 
semicircular extremity, from the base of which powerful 
steam jets are escaping ; but there was no evidence that 
it was prolonged by a crack or fissure, or fault, or other 
displacement of ground, nor was there any evidence that 
the fissure had been produced by any inequality of the 
movement of the ground bounding it, but rather that it was 
caused simply by the removal of material which formerly 
occupied its space. Its direction, as far as could be ascer- 
tained, is N. 50°E., which is the general line of direction 
that would connect all the more active geysers between 
Tongariro and White Island. 
“TV. Matter ejected during the Eruption.—Vhe quantity 
of matter which was ejected during the different phases 
of the eruption was very large. In the first place, stone 
fragments were scattered from the earlier eruptions of 
Tarawera over an area of country extending to the east- 
ward as far as Te Teko, and even, some say, to Fort 
Galatea; while in the opposite direction they are not 
reported to have fallen at any place farther west than 
Wairoa, a distance of six miles. None of the fragments 
which I collected are other than portions of rocks of the 
district, nor do they present in the slightest degree the 
character of volcanic bombs or lapilli formed from lava or 
rock material in a state of fusion. Yet there can be no 
doubt, if we can accept the evidence of the eye-witnesses, 
that these rock-fragments must have, in some cases, 
reached the ground in a partially incandescent state. 
Next followed the great ejection of pumice-sand, which 
forms enormous deposits in two localities: the one is on 
the eastern slope of Tarawera Mountain, already de- 
scribed, the nature and origin of which I had no oppor- 
tunity of ascertaining; the other deposit of this nature 
is chiefly on the western side of Rotomahana fissure, and 
was no doubt ejected at the commencement of the second 
phase of the eruption. Over a district of twenty-four 
square miles south of Tarawera Lake, and on an almost 
equal area to the north and east of the lake, the whole 
surface of the country has been covered with this pumice- 
stone so thickly as to obliterate in a great measure the 
natural features, partly filling the gullies and enveloping 
all the hills as if with a deep mantle of snow, so that not 
a trace of vegetation can be seen, from the highest peaks, 
such as Te Hape-o-Toroa, which is 2300 feet above the 
sea, down to the level of the lake. The thickness of this 
deposit could not be ascertained at the time of my visit, 
as no slips had occurred in it and no sections were to be 
seen. It consisted of fine-grained and gritty pumice-sand, 
slightly crusted on the surface by the action of the rain, 
which also caused it to assume a slightly greyish tinge ; 
but underneath it was a pure white, and at a depth of 
12 inches to 18 inches from the surface had still a high 
“Tt is only by occasional glimpses during the breaks of | temperature on the sixth day after the eruption. 
