The Union and journal. [volume] (Biddeford, Me.) 1858-1882, 1869-03-12
Hoo IL. Florida Keys eer. Formed.

anu ue was OUlkcu w iSoNS hSAs
Hoe the Florida Keys rere Formed.
+ ny MRS. T.. G. AoAssIZ.
Just outside the lower extremity oi
Florida are great number Of Islands
the eastermost almost touching tho main
land, while the western lie little farther
Of. H
In consequence Of this pecu!larity Of
their disposition, the space left between
these islands and the Florida coast, mark.
ed on the map rs mud flats, Is broad and
open ut the western outlet, but almost
close towards the east. It Is important
to remember the form Of this broad, In
tervenIng space, stretching between the
keys and the mainland, because the mar.
rover and more shallow end may easily
be filed up with sand, mud, &C. II you
look at the map, you will see. by the fats
at the eastern end Of this once open chan
mel, that such a process Is actually going
on. In fact. a current sets towards the
channel. drifling Into It sand, mud, and
debris of all sorts.
Ihope to show you that these flats, be.
Ing gradually consolidated into dry land,
will at last make bridge between the Is.
lands and the lower extremity Of Florida,
uniting them solidly together, so that the
former will cease to be islands and will
become part Of the main land.
Indeed we shall find that Florida her
self, so far as her structure Is known, Ii
only succession Of such rows Of Islands
rs now lie outside her southern shore
united together by flats exactly like those
accumulating at this moment between thu
present islands and the coast. These Is
lands are called the Keys Of Florida, ant
are distinguished from each other by ;
variety of appellations, such rs Sand Key
Indian Key, Long Key, Key West and thu
like. They are Of various sizes; some
like Key West, for instance-are large In.
habited islands, planted with fruit and
flower gardens. where coacoa-nuts and
other palms, orangc-trees, and bananas,
grow In luxuriance, while others are mere
barren rocks scarcely rising above the sur.
face of the ocean, washed over by the
waves, and wholly destitute Of yerdurc.
Suppose now that In fancy We sail oui
from the keys on their seaward side
choosing bright, calm day, when tn,
surface of the ocean Is still. The water,
Of that region are always remarkably
clear; and under such influences Of SKY
and atmosphere they are so Transparent
that the bottom may be seen at 4 consid
cradle depth, distinct as picture under
glass. '.''
Sailing southwark to distance Of some
four or five miles from the keys, we find
ourselves In the neighborhood Of rocky
wall rising from the ocean bottom. Az
we approach It, II we look over the sides
of the boat, we shall see that we are pass.
Ing over floating shrubbery, branching
growth spreading In every direction, Its
lighter portions swaying gently with the
movement OF the sea. 1t is not green like
land shrubbery, but has variety OF soft,
bright hues-purple, rosy, amethyst, yel.
low, brown. and orange. II circumstances
are favorable, and the water crystal clear,
rs It sometimes Is, VIC shall have glimpses
Of brightcolored fishes swimming In and
out amid this tangled thicket, or here and
there we may discern variety Of sea-ar.
cmones, their soft, feathery frinses fully
expanded.
This wonderful growth over which we
have imagined ourselves To be sailing Is
the top of u coral wall. Reaching The
surface Of the water ut intervals, 1t forms
little rocky islands here and there. divided
from each other by open channels, through
some OF which vessels OF considerable
size may pass. This wall is In fact a rep
etition of the same process as that which
has formed the inner row Of keys, though
In more incomplete stage; It Is built up
by the little coral animals from the sea
bottom. Wherever circumstances are
most favorable to their development,
there they grow most rapidly. In such
spots they bring the wall TO the sea level
aAnnar than IL, nthnrs
This done, however, the work of the
coral animals ceases, because they can
not live out Of water. But In consequence
Of process Of decay aud decomposition,
which I shall describe when we examine
the structure and life Of the animals them
selves, such q wall-or coral reef, rs Il Is
called-ls surrounded by coral sand and
fragments worn away from II by the NC
tion OF the sea.
Material Of this sort, mixed with sea-
weed. broken shells. &C., soon gather up
on the top Of the reef wherever the coral
growth has brought It to the sea level.
by degrees u soil Is collected upon such
spots. raising them more and more above
the surface OF the water. In this way the
Islands have been formed which We call
the Keys OF Florida; and In the same
way the little patches now rising highest
on the summit Of the Reef will enlarge
into more aud more extensive
islands, though at present many Of them
are scarcely above the water level.
IN E<pessiec BreakIsss.
1t,i,os. saa.,- IN n. lie. ia