The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1900-08-08

at first must have been inter-
mittent with long quiescent periods, to
enable the shore to have been repopu-
lated with molusks and corais." Those
mollusks and corals are found In the
layers of breccia and were evidently
fragments Of the coral reef through
which the eruption of the crater had
torn its vent.
Mr. Dali evidently lacks the proper
conception of the process of formation
of tufa cone like Diamond Head.
That process is extremely rapid. The
hot mud Is driven high into the air.
and falls I'm vast showers around the
vent building up a ring of soft, lam
mated tufa rock, which at once ce-
ments and hardens. If the showers of
mud were intermittent, with long quiz
escent periods intervening, that would
be evidenced by layers Of soil inter-
posed between the laminae or strata of
tufa, which Is not the case. Diamond
Head was evidently the product of
single gigantic explosion. and not of a
protracted succession of volcanic ac-
tivitfes. 1t Is older than the. Koko
Heads, because more deeply fiuted by
weathering, but cannot be older than
the |leistocene. Mr.. Dali may be COR
rect In referring to the extinct fossil
species of oyster found in some Pearl
harbor beds, to the Pliocene But he
IL probable that Oahu was land, inhab-
ite- by animals, as early as the Eo-
Gene. The immense erosions of Oahu
prove a great antiquity-but, the Eo-
Gene?
| DIR. Hitchcock seems disposed to ac-
lcept the hypothesis of Professor Agas-
siz that vast aggregations of limestone
accumulate on the ocean floor, and by
] their weight engender assures through
which volcanic eruptions break forth.
DIR. III. thinks IL not improbable that
such limestone beds underlie the noun
tains OF Oahu. But the evidence seems
to confine the existence of limestone
beds to the fringing coral reefs. 1t Is
characteristic of the secondary craters
along the shore to have discharged
great quantities of limestone, coral and
shells. But no calcareous matter seems
to have been thrown out by interior
craters like Tantalus or Luakaha. II
the vents Of those craters came through
limestone beds three or four miles be.
low. surely some fragments of the
white rock would have been torn of
and brought to the surface. / hav,
never seen any trace of calcareous mat
ter In the older lavas OF our mountains
There Is certainly none in the varied
ejecta of the great explosion of 179
from Kilauea. i think those alleged
limestone beds under our mountain
have no existence.
DIR. Hitchcock's four pages on our ar
tesian wells are highly instructive an,
embody a quantity of important facts
He finds no law for determining tn
derth of the wells. There does seen
! to be general rule that the deepe
wells are those farthest seawards fror
, the general slope of the mountain mas.
On pages 55-57 is an "Order of Event
> inatne Geological History of Oahu.
+. Seventeen numbers are named I'm tn
2 series. We should make the ''accumu
n lation of dunes" in IL precede the "de
n preston in 16, for reasons indicate
I above. The whole discussion is care
: fully arranged and easy TO understand
q IL should be widely read and studie
y by residents of Oahu to obtain an In
I teIngent apprehension of the rocks col
: stantly in sight.