Evening star., 1897-03-26
HAWAIPS FERTILITY
The Black Loan and Sand From the
Lava Flow.
WHAT UNDERLIES RICH PLANTATIONS
Use Of Artesian Wells to Irrigate
Coffee Fields.
R CHI, STRONG NDS
Special Correspondence Of The Evening Star
ry0Ay0T IYv TT 1Ho,.l "a 20

The geological formati of the Hawaii
an Islands may be mainly expressed by one
word-lava. The mass of the entire group
is built up of that one mineral In its nu-
merous varieties. not greatly differing from
each other. A one-hundredth part may be
composed Of volcanic ashes and tufa, which
are only what might be termed the frotE of
lava. Perhaps one-thousandth part may
be calcareous coral and shell sand, some
OF it oemented into sandstone.
Lava is the rock that wells up through
the shafts of volcanoes, white hot from the
molten interior twenty-five miles beneath
the crust. 1t spreads out and cools in vast
uneven beds of rugged rock, full of vesces
or spongy cells, except where 1t has filled
some deep cavity where the pressure COM
pacted 1t. This lava rock is very COM
pound, a mixture of almost all known min
eral elements, but none of the valuable
metals, except iron in more than homeo-
pathic quantities. And the iron is only
enough to color it red when oxidized
Hence none of these Hawaiian rocks have
any mineral value, and there is no work for
the miner. Much of the more compact
lava Is available as an excellent building
stone. very durable, and hewing more easily
than granite. Honolulu is studded with
ne" business blocks fronted with this
blush gray lava, of which we have noun
tainsful. Several beautiful public editices
are built entirely of it,
Perhaps our five hundred cubic miles CT
these lava rocks contain as much gold as
does sea water. and as equally dffused.
peileVe there are several thousand billions
OF gold in the ocean. but its profitable ex-
traction is hopeless. Nature has a mar
Veious alchemy by which in the lapse of
millions of years the vast plutonic rock
masses of the continents once lava like
ours, undergo slow secular change and.he-
come transformed. and veins and lotles of
nd
'heir recessAs. Here our rocks are young.
per1aps none OF them a million wears old
and can yield nothing for the miner. nei,h
tr scia IRON coal nor jewels. There are
no strained rocks, because nc LAYERS have
been deposited by water excepf what is
sun beneath the ocean. Yes there are
strata OF tu1a in very even layers These
laihed l down from the atmosphere in the
ioiin OF not mud. which was spouted miles
aloft In volcanic throe and cemente1 as
1t zen, o1ten lncasing many square miles of
SCH surrounding the fiery vent There arc
several i't square miles on the Oahu railway.
Just out OF town. which are covered bv
from SIX to twenty feet of these LAYERS nf
solt rcck, which overie great thicknesses
OF alluvial soil, or of coral.
The Site of Honolulu.
Much OF the fiery mixture of lava and
water, shot forth from sudden cruptions Of
the explosive kind, so expanded while a,oft
as 10 cool In the form of spongy sand or
Volcanic ashes. before falling. This citv
or Honolulu rests upon such bed of from
three to eight feet of black ashes or sand
everything coral On lower Fort stree. tho
eeilar OF a new brick block is now being
excavated. 1t goes through eighteen inches
OF brown loan, then four feet of the bla ok
sand The upper loan is only the black
ashes decomposed by air and moisture ,Tbe.
ashes or sand will mostly be sifled for
mortar. The coral below this will be level
ed 10 the proper depth. This coral sub
stratum was ancient reef formed under
water, but now raised considerably ahoye
sea level. The whole of this Island of Oah,,
had originally undergone a slow subsistence
perhaps for half million of years. settIinp
many thousand feet, as is we'll ascertained
AL very recent period however proba bIv
not over 500 or lO,UO years, there was
an apparently quite sudden elevation of the
whole island. varying in parts from thirty
TO nifty feet. This converted into dry land
large stretches of what was the frtnpinp
reef. II is not exactly true cora, bnt a
ccncretion of fragments Of coral shells
madrepore tubes, and cacareous mud
forming coarse. whitish rock Most of
this coral within the town became buried
deeply with the black cnders or sand.
which seem not long after to have been
shot up from the great cinder- cone inland
ABOUT 2,Tn feet high. known as Mount
Tartalus.
The main mass of the volcanic noun
tains forming this island are. evidently
many hundred thousand years old. as in
uiIdteu ny tHe great extent to which it has
Weathered away. under the slow erosion of
rain storm! and the torrents generated by
them Except near the bases of the origi-
nal mountain dome. no traces remain of the
once rounded form. Only sharp serrated
ridges are left where the now wide gulches
nave eaten into each other. Many of these
ancient ravines have had their outlets at
the shore obstructed by very recent tufa
cones such as Diamond Head and Punch
BOWL, which form such conspicuous land
marks to Honolulu. In such cases new
outlets have been formed for the streams.
There seems to have been very recent
period OF fresh volcanic convulsion around
the shore Of the island. perhaps coinci-
dent with the changes attending the close
of the glacial period.
nile III this city the foundations of most
or the heavier buildings extend down to
the solid coral this Is by no means neces-
sary. The black sand is itself so compact
as 10 furnish safe foundation for the
heaviest structure. Our builders long ago
learned to rely on its solid qualities Both
or the massive churches, the Central Union
ard the Anglican Cathedral, rest upon
th's sand neat story is told about the
latter AFTER the heavy foundations of the
catneoFaI mad been finished, some thirty
years ago. the good Bishep Staley's mind
insgave him. He began to Institute further
inquiries about the sandy basis on whic1
Inose foundations rested. Among other
persons ne resorted to the Catholic bishop
VINO re1oiced in huge cathedral OF his
own. Bishop Maigret, will you kindly in.
FORM me whether the founda ton of ycur
cnurch goes down to the rock or rests unon
the sand? "Our church," the old preiate
ponderously responded, .is founded unon
the rock. He scored one that time for ST
Peter. ''A ~
This black ash is an admirable fertilizer.
although 1t is slightly poisonous TO yegeta.
tion until decomposed by exposure to air
ana moisture. Hence the roots of trees sell
dom penetrate 1t. Volcanic ash OF li,,a
structure, but more commonly yellow ex-
lists In several other localities. and i. al
ways extremely fertile. There are about
-FOUR square miles OF such soil under the
prosperous Haua plantation, at the eastern
argyle OF Maui. where the country is warty
with cinder cones. At the southwest angle
OF the island Is nearly as much more A.
kau. on the south end of Hawaii. is a re-.
markable deposit of yellow ash covering
over lOO square miles to a depth of ten to
thirty feet. This must have been the ef-
feet OF single explosion Of a few hours,
duration comparable TO the enormous over
throw of Krakatau in 1883. 1t probably
took place not far from a thousand wears
ago. This kau ash Is excessively nro-
ductive. but unfortunately receives scant
rainfall In most parts, while Irrigation is
forbidden by the impossibili.y of water col
lecting on the new lava Of the rainy forest
uDlaud8 in the int