The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1909-09-24

usher 81 that rrWAfkhblt doom hN WI
liam I.owthan Green, entitled ives
tiges Of the Molten Globe which pre-.
sents windy the so-called tetrahedral
theory TO account for the shape Of the
earth.
Professor Hiichcock's new volume
Is strictly eclectic. The work Of the
author in the field has been primarily
geological and be presents his results
In the first part by means Of concise
statement of the physical geography
and structure Of the Islands. Each
Island is treated separately including
the low islets and reefs which extend
far TO the northwest, and a fairly com
plete discussion Of the geology of Oahu
is given, with notes on the artesian
waters, and a discussion of the small
extinct craters such as Punchbowl and
Diamond Head. The greater part of
the remaining text of the book is
taken up with orderly compilation of
the statements Of visitors to the sew.
eral volcanoes of the Island of Ha-
wall and some discussion of the sig
niicance of these records.
The Geological History OF Oahu.
Professor Hitchcock's personal work
is well illustrated in his summary of
his geological history of Oahu. There
was probably submerged Tertiary land
and through assures in it lava poured
out in sheets until finally the Island
of Kaala arose, which became wholly
covered by vegetation. Wind and rain
channeled the slopes Of this dome and
then new piles of lava arose nearby
and Koolau was formed which extend.
tended out TO sea several miles farther
to the northeast than at present.
These new lands attracted corals and
shell6sb which have been piliDg lime.
stones against them ever since, but
the volcanic activity was not ended,
and porous basalt was poured out at
the Pail, rising through cracks, and
making the fssure filings which have
J since been revealed to us as bikes; in
some places large lenses of lava are
squeezed between old flows. Then came
the beginning of explosive eruptions,
and volcanic pudding stone was form.
ed by the broken pieces hurled out,
seen typically at the Pail, and over
very wide areas red ash, clinkers and
; lava were spread out such as are seen
in the Laeloa and Tantalus craters.
This kind of activity went on at diff
ferent times finally forming tuff or ash
craters, typical cinder cones such as
Punchbowl, Diamond Head and Koko
Head. The matter which formed them
was blown through assures, even
through the coral reefs, so as to bury
some of the reefs. Meanwhile the
land was enlarging, and new reefs
were formed, all decomposing to form
soils: discharge of ashes and showers
of stones became dominant over the
lava flows, so that the latter had to
content themselves with filing assures
underground which have since been
? revealed by erosion. Great warnings
of the earth s crust produced n depres.
sion of the land beneath the sea to the
, extent of some $50 feet followed by
elevation to the present level. The
last stage in the history of the Oahu
is the erosion by wind and rain at the
present day and the accumulation of
sand dunes.
biologists may differ, as to detail,
from Professor Hitchcock, but this his.
tory of Oahu probably typifes the his.
tory of the whole group of Islands
and is valuable and detailed study.
The History of Mauna Loa.
The history of Mauna Loa, the great.
Z est active volcano in the world, shows
. succession of recorded events from
. 1880 to 1907 inclusive. Like all such
histories, the records prior to the mid.
die of the 10Th century were very
scanty. Since that time they are in.
creasingly full, so that it is difficult to
base on them any cumulative general.
20
of ernptions. DR.. Hitchcock summarizes
as follows the mechanism of develop.
ment OF the typical Hawaiian volcano:
:" At first there is a small crater dis
charging lava from the summit of the
dome.
Secondly, the lava is not produced
in sufficient quantity to flow over the
margin, the opening is sealed and then
the outermost crust breaks up. The
crust is too vast to be absorbed. Blocks
of il will be elevated; other sections
will be absorbed and the outer wall on
the makai (sea) side may give way.
There will be discharges on the lower
side. This may be the Mohokca stage
Thirdly, all the segments Of the
crust fall into the reservoir beneath
Vertical walls encircle the pit. This /,
the stage of Kilauea and Mokua
weOweo
"Fourthly, the cadera with encir
cling walls is formed but the lowel
walls give way. Great rivers of layi
flow TO the sea, As the fires die dowr
several craters are developed on thu
principal floor, This is Haleakala
Filthy the eruption OF the smaller
craters multiply and the whole pit Il
filed. The caldera Is smothered. IN,
smaller craters continue 10 be developed
until the internal reservoir is exhausted
This IL the Mauna Kea stage"
This description Of the sequence Of
events is somewhat too concise and tn,
reviewer believes that DIR. Hitchcoel
has not laid stress enough on tn
growth Of explosive activity In th
llaleakala and Mauna Kea stages, Thi
was probably an oversight rather thai
q deliberate omission for ! have u
doubt that the author recognizes IN
explosive character Of the cindeT cone