New-York tribune., 1896-11-30
THE SINKING OF THE LOUISIANA COAST.
Y NJ Harrod in The New-Orleans Picayune

Is nj. 4
good deal has recently been said about the SUBJ
sdence of the surface OF the earth in this vicinity
Some Of this has been Of asms sys
II not important, beg that may be allowed 10
contribute
engineers that there has been. and probably still
continues. slow subsidence OF the guf coast 20 s 70
ida 1t has not been as clearly recognized 10 tne.
westward.
Among the evidences OF this may be cited the
well-defned layer of cypress stumps exposed by the
excavation for the main sewer In this city,
at n depth OF ten TO twelve feet below the gut
level the stumps standing in five or six feet OF salt
water at Point Chcot and other parts Of Breton
Island Sound: the layers of coarse grass disclosed
about twenty feet below lake level. by j. W. Put
man, when building Horn Island Lighthouse; me me
stumps found buried six TO seven feet under the
marsh along the southeast shore OF Lake Pontcnar-
train by the Northeastern Railroad when excayai; Ss
ing filling for their testle and the sunken smell
These objects could not have grown at the level
at which they now found. but as they are IN
other respects I'm a atural position. the conclusion
is necessary that the surface has sunk AT ire points
ment toned from six TO twenty feet
But as the Instances mentioned extend beyond the
alluval or delta formation into the coast piocen,e
Subject 10 geological subsidente from other causes
than the work OF the Mississippi River. 1t Is cos
Such movements. either of subsistence or OF ele;
vation are known to be going on IN many parts ot
the world The northern coast OF sweden Is rlshs'
while the southern is sinking. The coast Of Green.
land and of North America down TO New,JerS,ey Is
subsidng while In the Pacific Ocean some islands
are undergoing depression and others elevation.
These movements also observed 10 a!teriid.e'
Fxcept in a few cases. where exact and long-cotn.
tin,,ed observations have been maok. neither tno
rate OF change nor the limits OF its enect nave oeen
determined But in all instances 1t Is 100 SLOW 70
Influence the design or construction OF woThs LUZ
mans use - -. ,, -, = Altar.
But there IL another change OF level OF dins. H,
ent character. going on In this vicinity. Inc AIIs
sissippi River is constantly pouring down an M
mense quantity OF mud which is largely disposed o,
in the formation OF the bars and banks ABOUT tS az
mouth This has been estimated at about f50V"oy9
tons per year This stuff Is finely comminuted ara
very compressible in mass. Not only doeS ~ seot go
under it's own weight. but at and about rort r.aa'
large loads have been imposed on II. buidlnss ."
chinery coal and great many Thousand toils y.
ballast These natural and artihciai causes uns eus
bned have undoubtedly produced locai con.pars o.s
sion and depression The vertical rate OF tnis vs
ment has been as ,ertaned to be about tnIeeelut
ters OF an inch per year. or from fourteen 70 %
inches in twenty years. but how far iniand; ot ~
the river IL extends has not yet peen esta
Probaby II Is most acute at Port Eads iroth rv .v
ARTIFICIAL causes Just cited and extends graus.
Iessenng until II dies away higher up ine i'e'
u,hera TIE deposits are older and more soldihed.
This movement of the earths surface Is ioCa i
need not be encountered except In ensihee'"s
construction about the mouth or tne risen pive-
In the eariy months of 1888 the Mississippi Kvrs M
Commission ran line Of precise levels from New 'm
orleans to the end Of the east jetty II is tner IN
tenton to repeat this line In 1898, after an nterS
of ave wears The work Of repetition VIII propavn,d
he extended to the hills at Baton Rouge or peywa
any suspicion of subsidence. More exact inio'isW W
lion will then be on hand. In the mean uhs, - ~
not thought that either OF these movements u ,,v
10 affect the present or future S'ao'"~