The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1870-01-29
Tie Reef.Building CoraIs.

The variety of compact and branching
corals far exceeds description: 100 species
are inhabitants of the Red Sea alone, and
an enormous area Of the tropical Pacific is
everywhere crowded with the stupendous
works of these minute agents, destined to
| change the present geological features of
the globe, as their predecessors have done
in the remote ages of its existence.
Four distinctly different formations are
due to the coral-building polypes in the
Pacific and Indian Oceans namely, lagoon
island or atells encireling reefs, barrier
reefs, and coral fringes, all nearly confined
to the torrid zone.
| An atoll is a ring or chaplet of coral,
nclosng lagoon, or portion of the ocean,
in its centre. The average bredth of that
| part of the ring which rises above the sur
face Of the sea is about quarter of a
mile, often less, and it it is seldom more
| than from six to ten or twelve feet above
the waves; hence the lagoon islands are
not visible, even at a very small distance,
unless when they are covered by the cocoa
nut palm, or the pandanus, which is fire.
| luently the case. On the outside, the ring
or circlet shelves down for distance of
one or two hundred yards from its edge, so
that the sea gradually deepens to about
| twenty-five fathoms. beyond which the
sides of the ring plunge at once into the
unfathonable depths of the ocean, with
mere rapid descent than the cone of any
volcano. Even at the small distance of
some hundred yards, no bottom las been
reached with a sounding line mile and
half long. All the coral in the exterior of
he ring, to a moderate depth below the
surface of the water, is alive; all above it
is dead, being the detritus of the living
part. washed up by the surf, which is so
heavy on the windward side of the tropical
islands of the Pacific and Indian Oceans,
that it is often heard miles off, and it is
frequently the first warning to seamen of
their approach to an atoll.
The outer margins of the Maldive atols,
consisting chiefly of millepores and porites,
are beat by surf SO tremendous that even
ships have been thrown by single heave
of the sea, high and dry on the reef The
waves give innate vigor to the polypes by
bringing an ever-renewed supply of food
to neurish them, and oxygen to aerate their
juices; besides, uncommon energy is given
and maintained by the heat Of tropical
sun, which gives them power to abstract
enormous quantities of solid matter from
the water to build their stony homes, a
power that is efficient in proportion to the
energy of the breakers which furnish the
supply.
On the margin Of the atolls, close within
the line where the coral is washed by the
tide, three species of nullipores flourish;
they are beautiful little plants, very COM
mon in the coral islands. One species grows
| in thin spreading sheets, like a lichen; the
second in strong knobs as thick as mans
finger, radating from common centre;
and the third species, which has the color
Of peach blossom, is reticulated mass of
stiff branches about the thickness of
crows quill. The three species either
| grow mixed or separately, and although
| they can exist above the line of the corals,
they require to be bathed the greater part
Of each tide; hence, a layer two or three
| feet thick, and about twenty yards broad,
formed by the growth of the nulliporos,
| frnges the crclet Of the atolls and protects
| the coral below.
The lagoon in the center of these islands
is supplied with water from the exterior,
by openings in the lee side of the ring, but
as the water has been deprived of the great
err part of its nutritious particles and inor-
ganic matter by the corals on the outside,
the harder kinds are no longer produced,
md species of more delicate forms take
their place. The depth of the lagoon varies
from fifty to twenty fathoms or less, the
bottom being partly detritus, and partly
live coral. In these calm, limpid waters
the corals are of the most varied and deli
cate structures, of the most charming and
dazzling hues. When the shade of evening
comes on, the lagoon shines like the Milky
Way, with myriads of brilliant sparks
The m s.rocopic medus;e and crustaceans,
invisible by day, form the beauty of the
night and the sea-father, vermillion in day
light, now waves with green, phosphores-
cent light. This gorgeous character of the
sea-bed is not peculiar to the lagoons of the
atolls; it prevails in shallow water through
out the whole coral-bearing regions of the
Pacific and Indian Oceans.
Encircling reefs differ in no respect from
the atoll ring, except in having islands in
their lagoons, surrounded also by coral
reefs. Barrier reefs are of the same struc-
turc as the atoll rings, from which they
only differ in their position with regard to
land. They form extensive lines along the
coasts. from which they are separated by 4
channel of the sea of variable depth and
breadth, sometimes large enough for ships
TO pass. \ very long one runs parallel to
the west coast of New Caledonia, and
stretches for 100 miles beyond the extremi-
ty of the island. But barrier reef off the
northwestern coast of the Australian Con-
| tinert is the grandest coral formation ex-
istin.g Rising at once from an unfathoma-
BILE depth of ocean, it extends for 1000
miles along the coast, with breadth vary
ing from 200 yards to mile, and at an
! average distance Of from 20 to 60 or 70
miles from the coast, the depth of the
channel being from 10 to go fathoms. The
pulse of the ocean, transcendently sublime,
beats perpetually in peals of thunder along
that stupendous reef, the fabric of almost
microscopic beings.-Nrs. Somercile.
The lady principal of school, in her
advertisement, mentioned her lady assis-
tant, and the reputation for teaching
which she bears but the printer left out
which so the advertisement went forth
commenting the lady's reputation for
teaching she bears.'
SYMPATHETIC Roy Frank said a
mother to her little ten-year old son, the
other day, in reference to an old blind dog