New-York tribune., 1842-03-29


.re The points in the cncircling rect upnn which
r.,,y cocoa trees. &c. and inside, or between {
a,,d and the sides of the island, Ia shallow sea
communicating with the ocean through occaslona
oncsppes. similar to those met with IN the lagoon
Nov, i was !, rule laid down by DAMPIER and
o,bcr noyirn,ors, that near high and bold coust,
wc shall have u deep sea; while along gently
sioning coasts the sea will continue shallow '"l
Some distance from the shore. lt was tllerelor'
surprising that when we had on island hNe liia
rcnresentcd in the figure going down at so steel
nm angle instead of deep water, we ilnti IL si'ai
~, C;o Two or three miles away, and still tn,
wnteris shallow, and we have coral bottom. Bu!
co heyond the reef, and down goes the llne some
thousand feet 1t is obvious that the coral alone
il the cause of the shallow water; and we mast
account bv means Of the coral tor the tact tlal ~
q distance from the island, instead OF several thou
sand feet of water, as we are entitled tG expect.
we come suddenly to bottom Now IN wtia'
manner can these zoophytes, winch cannot I'VE al
q greater depth than 100 feet below the water, be
able to build upa reef two, three, tour or more
thousand feet eigh from the bottom because tle
belief of FLINDERS that these creatures could work
in the deep, dark, cold ocean and build up then
structures to the light AND heat is proved not to ho
true; though he did not as geosraplier IN il1s
statements respecting these bold coasts
DARWIN here suggested simple hypothesis
which clears M the whole difficulty. Suppose the
coral TO begin TO grow at or d, IN the flS1rc
,bovo and suppose these points al tAat tme M
s,ead Of being l500or 5000 feet deep, to be within
oO feet of the surface the then standing at u
different relative level from that wh'chlt occupie-
now. In short the superstition OF a $tn6'Rg dorm
Of the land will expaini,all. When the land be-
Sooto sink the corals building up, rs Is their
nature one generation forming on the. skeleton ''
the other, Jus, as peat grows uni!i II reaches Il
thickness of a hundred more ieet each success.
sive generation plants itself on the rcnains OF le
former Sowith coralS: each mass forms found
ation on which new Is built AZ hafe
shown, or as Niccelini has shown. the rate OF slb-
=sidence in the Bav OF Bate is hreeonrttlS ot ;'n
inch a yesr Now common CoralS will grow up
at that rate; and perhaps two inches year would
be a slow growth Let me observe that we need
only show that the greater part OF them increase
slowly; though passages of the Red Sea are known
TO have been filled up within a few years his,
however, may be easily explained, because the
waves, &C.. may have thrown up sand and thus
filed these passages Blu, the common growth rt
the coral is slow. Indeed EuRESnERG thinks that
some of the species as the Meand7ina are as old
ss the most sncent trees of Europe some of which
are three or four thousand years old DKcAN-
Do1.I.r has shown thar some yews and othe, trees
nre two thousand wears old, and some still more
ancient. So Ehrenbcrs thinks that many of these
corals in the Red Sea are several thousand years
Of age But the Sigor OF their growth sepends
unon the wrrnh and carbonate OF lime that reaches
them.
Now we may suppose the land 10 be sinking
down gradually as the co,als are building up
What is the consequences Instead of sinking
down with the land the corals will grow up by
building upon the ormer nlasSes-}usi rs one pave
ment of the Temple of Jupiter Scraps was built
upon the other, which had sunk six feet below the
level OF the Mediterranean And when thcS, CO.
rails come TO the surface and can rise no higher,
the waves then throw up calcareous sand upon
them and form ridge as in the lagoous. But
while 1hc corals are thus rising up, the mass al
ways gaining in hight above its original base and
yer remaining in other respects in the same posi-
ton, it is different with the land every inch that
il sinks is rrecoyerably lost, and the distance be-