Williston graphic. (Williston, Williams County, N.D.) 1895-1919, 1903-11-12
FORMATION OF CORAL.
Summary of Recent Studies of At0l1s
by Prof. Agassfx i'm the Vari.
Gus Oceans.

Prof. Alexander Agasslz has sum-
married. his results based upon obser-
yations of barrier reefs and atolls (coral
islands) carried on during the last rs ,
years, for the proceedings of the Royal
society. He recognizes the fact that
Darwin's theory does not explain tho
conditions now observed, but limits his
report to descriptions of the different
types of coral reefs and of their prob
able causes, without attempting to es-
tablish any Independent theory.
He has found, that the barrier reefs
of Fiji, Hawaii and the West Indies are
underlaid by volcanic rocks and usually
flank volcanic islands. Those of New
Caledonia, Australia, Florida. Honduras
and the Bahamas are underlaid by OUT
liers of the adjoining land masses.
Some of the barrier reefs of the Society
islands, Fiji and the Carolines show
that the wide, deep lagoons separating
them from the land mass were formed
by erosion from broad, fringing rect
fiat.
Encircling reefs, as in the Society
islands, hold to their central island, or
islands, the same relation which bar
rier reef holds to the adjoining land
mass, Denudation and submarine ero-
sion accounts for the formation of plat
forms upon which coral and other lime
stone organisms may build either barri-
er or encircling reefs or even atolls
rising upon a volcanic base.
We may trace plateaus that have been
elevated, like Guam, partly volcanic and
partly limestone, to atolls where only
small islet or larger island of either
limestone or volcanic rock is left to in
dictate its origin. Atolls may also be
formed upon the denuded rim of VOL
canic crater, as at Totoya, in Fiji.
Many of the atolls in the Pacific are
merely shallow sinks formed by high
sandbanks thrown up around central
area. Throughout the Pacific, the In
dian ocean and the West Indies the most
positive evidence exists of moderate
recent elevation Of the coral reefs.
Closed atolls can scarcely be said to
exist; Niau, in the Paumotus, is the
nearest approach to one, yet its shallow
lagoon is fed by the sea through its
porous ring. The land area Of an atoll
is relatively small compared with that
of the half-submerged reef flats. In the
Marshall islands and the Maldives,
for example, the land areas are reduced
to minimum.
Atolls may arise from platform Of
suitable depth wherever and however it
may have been formed and whatever
may be it's geological structure. The
great coral reef regions are within the
limits of the trades and monsoons and
the areas of elevation, with the excep-
ton of the Ellice and Marshall islands
and some of the Line islands. tCorals
have their fullest development on the
surface of reefs; they grow sparingly in
lagoons where coraline a1gae grow
most luxuriously. - American Geo.
graphical Bulletin.
Never Satisfied.
Hicks-I saw you talking to Growell.
just now.
Wicks-Yes; he was grumbling about
the weather, as usual.
Hicks-I wonder what sort of weather
he likes, anyway?
Wicks-The sort of weather he likes
best, it seems, is the sort we don't hap
pen to be having at the moment.-PhOae
delphia Ledge.