The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1900-09-06
N|NDDR|FTFD SAND-DUNES
AN INTERESTING GEOLOGICAL
DISCOVERY.
Or. Bishop Scores Geologist w. II.
Dali, Who Mistakes Wind-Action for
That Of the Waves.

EDITOR STAR; l desire to an
nounce a discovery of interest which |
believe to be quite new.
The mass of soft material in which
the road is cut from the south gate OF
kapiolani Park to the Light House il
wind-drifted sand-dune. 1t Dor
ders the seward base of Diamond
Head for one-third of a mile, reaching
from the beach to an average height OF
over one hundred feet. The blown or
drifted material of which il is COM
posed is a mixture of calcareous beach
sand with angular fragments of brown
tuh, the detritus from the tuft-c
above. The turf particles are largely
coated with white lime, which is from
the triturated sand The tuff forms
the great bulk of the material espe-
cially at the east or windward end The
lime was finer and lighter, hence was
blown farther than the coaIser tuft, and
forms a larger proportion of the ma
terial west of the beach residence of
Governor Dole.
The positive evidence of the wind
| drifted character Of this hill, is mainly
found in the internal structure of the
! mass, as disclosed i'm the exposures
made by the extensive road-cutting,
and in the intersecting gullles. This
structure is precisely that of the an
clently concerted sand dunes of Ka-
huku and Laie on Oahu, and of Wal
luku and Waikapu on Maui. One pc
culiarity is found in the layers of fri
able calcareous crusts, with soft mat
ter interposed. Some of the crusts are
of considerable hardness. second
characteristic popularity is found i'll
the constantly varying dip of the strait
fed layers, which are inclined in all
directions and at all angles. These two
characteristics are peculiar to old sand
drifts containing lime.
| The great denominations of beach
SAND east OF Diamond Head as well as
in the Park westward, together with
the fact of terrific wind draught in
storms around the Head, render it a
necessity that sand-dunes should ac-
cumulate in that locality And there
the sand-dunes are!
The special interest of this subject
| lies in the serious error made by the
Geologist w. H. Dali who visited the
locality in 1899, and published his re-
! port in Vol. IL of the Bulletin of the
Geological Society of America"
Mr.. Dali pronounced the mass in
question to be marine formation. He
says:
The conclusion to which came was
| that the whole mass of Diamond Head
had been slowly deposited in compare
| lively shallow water and gradually
| elevated. The election of material at
| first must have been intermittent, with
long quiescent periods to enable the
shore to be repopulated with mollusks
and corals"
OF course, the occasional ''mollusks
and corals" found in the great dune
We're blown up there in heavy gales. He
| oVerlOokS the obvious fact that If the
tuff had been slowly deposited" in the
sea- the surf would speedily have
ground the soft rock into fine mud. in
stead of leaving it in angular frag-
ments as it is. So he adopts the very
violent hypothesis that the sea then
stood at "a level perhaps 200 feet higher
than at present, and does this in the
face of the facts that there are no ma
! rine deposits in stu at that elevation,
along the foothills of the islands, and
also no traces of beach marks.
The beautiful symmetry of Diamond
Head both in it's rim and in it's con-
cave interior, forbids the notion of
intermittent" elections, whose vary
| ing force would inevitably break up all
symmetry. Like Kaula, Lehua, and
other tuff-cones that fine symmetry
could only be produced by a single,
| continuous, rapid election of the hot
mud raining down in uniform quantity
and distance for a very few hours or
days, and then ceasing forever Mr.
Dali is doubtless an expert in some
| lines of geology, but lacks the first no
! ton Of how our beautiful tuff-cones
were built
The usual elevation in such cones of
| the southwest side OF the rim above the
rest, was rightly attributed by Prof.
w. T. Brigham to the prevailing trade
wind driving an excess of the falling
shower of mud in that direction
Mr.. Dali failed to make right use
! of his eyes so as to see that the agent
arranging the foot hill in question was
wind, and not water. He fell into the
same error as Captain Dutton, who as
serted that the sea had once stood 200
feet above its present level at West
Maui, solely on the ground that he
found marine deposits at that height
along the slope at Waikapu. Those ma
rine remains were simply in the wind
drifted sand-dunes! Mr.. Dali, how
ever was much more eXcusable than
Capt. Dutton, because the Diamond
Head dune is greatly disguised by the
brown tuff and not readily to be recog-
niZed.
One learns much to distrust the con-
fident conclusions of visiting biologists
unfamiliar with local conditions.
Since the above was in type. it has
occurred to me that Mr.. Dali may have
mistaken the "friable crusts" for coral,
although the latter is hard and COM
pact
S. f, BISHOP.