The Elk County advocate. [volume] (Ridgway, Pa.) 1868-1883, 1882-02-09
Coral Reefs,

Coral reefs, said Professor LIE Conte.
of California, in q recent lecture. are
peculiarly dangerous to navigation be =
cause of their rising abruptly, so that
though the sounding line may show
5000 feet of water within half q. mile,
the reef may rear its perpendicular
wall for the ships destruction. The
most dangerous point for navigation
upon the face OF the earth is the reefs
of Florida. There are more wrecks
upon that coast than in any other por-
tion of the world. The largest town in
Florida, Key West, is built upon coral
reef, on account of the frequency of
wrecks upon the coast. If it was not
for the wrecking business the town
would net exist. With the exception of
cocoanuts there is absolutely nothing
raised upon the reef. The wreckers
came first to prey upon the wrecks,
then came merchants to prey upon
the wreckers, next lawyers and doctors
to prey upon both classes, and
finally the clergymen to pray for all.
The subject of corals was, also, the
professor said, OF scientific interest, be-
cause in these coral reefs We hold the
proofs of the vast oscillations and vari.
ations in the earth's crust, on scale
of which we have no other evidences at
all.
A very widespread misunderstanding
exists as to the manner in which reefs
are formed, one which has entered into
the public mind, and OF which it is al.
most impossible to dispossess the pub
lie mind. The idea is that these ami
mails are little insects that they build
like ants and bees do, and when they
are alarmed they disappear into their
little burrows, and these reefs are ac-
cumulations of millions of these little
insects in generation after generation.
| shall show that t, ERE is not the sem-
blance of truth in this idea.
The professor then explained that the
coral animal is polyp belonging 10 the
group of radiata that it consists Of
limestone deposits in the shape of
hollow cylinder with top and bottom
disks, surmounted with tentacles, con-
tanning a stomach and enveloped with
gelatinous organic matter. The tent
acles or arms arc provided each with g
mouth for the absorption of food. The
coral is cJraline limestone after the
geIatinous organic envelope is decayed
and removed. The animals which build
reefs are not much larger than pnheads
The development and growth of the
coral tree and head coral was clearly ex-
planned, showing ii to be analogous to
the same process in vegetation. It was
further explained that coral formed and
threw off eggs, which 6oated to some
suitable place, ana there began the pro.
cess of development independently,
forming new colonies, which in time
connect and form reefs, upon which are
deposited accretions, in time building
up keys and islands.
Reef building colals will not grow at
depth of over 100 to 100 feet. There
have been reef building corals found
at depth OF 1000 feet, but they were
dead-drowned by being carried beyond
their depth. This confines them to
coast lines and submarine banks.
Corals will not grow where the temper
ature is lower than sixty-eight degrees
at any time, that is the ocean, not the
air. Therefore they are confined to
the tropical regions. They will not
grow except in clear salt water; hence
there is always break in reefs opposite
the mouth OF river Finally, they
demand free exposure to the beating of
the waves. The more violently the
waves beat the more rapidly the corals
grow, because the agitation gives them
ventilation. Corals will grow in the
face of waves whose beatings would
gradually wear away wall of granite.
The four kinds of coral reefs found in
the Pacific ocean are fringe reefs, bar.
rier reefs, circular reefs, inclosing
lagoons in the ocean, and small lagoon
less coral islands. The explanation of
the formation of the three last named
will form the subject of the next lee
ture.