Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1850-12-21
MUD ISLANDS AT THE MOUTH OF THE MIS-
SISSIPPI RIVER

FROM THE NEW ORLEANS DAILY CRESCENT, NOVEMBER II.
November A, 1868 p. M
MEssas ED1roas This afternoon we spent a short time
in the examination of one Of the many mud islands" that
appearing and disappearing about the mouths Of the Passes
Of the Mississippi river Our survey brought tomany
Of them, and the time spent one, to which attention
had been directed by Capt La F., who had previously
amined it, certainly well compensated, compliment
cannot pay to the survey ITSELF
For the benefit Of those who may have read of
those mud humps, or some call them sand blows
let me premise that they appear and disappear suddenly
compared with the usual history Of island growth even
the Mississippi river For instance, having about two
hundred feet diameter the island below described has
appeared within years. risen elevation of six feet
above the Gulf water, and is fast being removed by
waves, weather. and sinking Others have much greater du
ration and become permanent additions to the crescent banks
along the Passes.
Artesan Isle as we have named this first made its ap-
peaance in and has pretty well maintained its form and
dimensions TO the present time It has length of about 600
feet width Of about $50 feet and present maximum height
of Z feet inches
Not far from its eastern end there is salt spring. which
forms the leading feature of the island and furnishes its only
obvious solution.
As you approach it. appears two three feet
high and Of SO feet base from the summit Of which you
buildings and view you find that thin dark lead
colored mud slime being constantly discharged with
casiona emissions Of gas the mud running suggshy
and flowing down the sides Of the cone until the waters
evapoas and leave the mud to form permanent additions
to the growing This process continues in each
till the reaches altitude of feet above the
waterleve when the spring breaks out in less elevated
place. to The surface Of the island has evil
dences of many such tuu having been formed upon it. yet
the Of the island has not thus been formed On the
contrary the mud islands often show themselves first without
springs rising in hemispherodal form from the water aud
the springs appear subsequently, In other cases. however,
the springs discharged into the Gulf water without
producing island the mud if any is discharged, being
carried away by waves and currents
The WATER when settled very strong salt water, without
foreign aae and upon the drying mud and clay the whole
island gistens with crystal salt The mud forms blue clay,
which aans great hardness being dried and burnt but
retains intense salt after being baked into solid brick
The sediment Of the spring almost destitute OF sand but
mixes with the deposes of the Mississippi and aernaes with
its sands forming laminated clay, breaking does
the surface into dscoda fragments and crescent sepaa OF
many curious forms.
On sounding the spring. which did by constructing
bridge the lead sunk IS feet and slowly ceased to
descend Others have sounded with larger lead twenty
five fahoms Below that depth either the mud thickens
the direction of the channel changes that soundngs are
not practicable In the of 25 fathoms sounding the
lead could not be Withdrawn, but adhered till its strong line
parted
Islands this character only about the Passes
wherever there is great amount of sedmenary matter
deposited In the shallow bays either side Of the river
there visible If any have heretofore formed, when
their margins in position similar to the banks along
4
waters, or have sunk by their specific gravity.
When any of these islands to be supported by dis
charging springs they disappear from these two causes
The mud islands to have escaped the searching
Of Mr. Lye and the solution given by Dr. Drake Of these
wonders is to unsatisfactory My previous cur
sorry examination led to the conclusion with him.
Blu, satisfied that the assigned by him are
not adequate to the effects produced.
offer hypothesis based geological considerations,
without attempting here to demonstrate its reasonebeness.
Those who know the geology Of upands north Of
the Gulf and Of the river need not be told Of the salt
springs that abound in the tertiary beds in middle and north
ern Louisiana. The beds from which they issue dip south
ward and disappear beneath the duya and aluvial beds
about latitude 81 degrees north.
Further NORTH throughout the States Of Arkansas and Mis-
souri, saerous group underes the coal measures and
many places the rupture Of the superintendent beds permits
the salt water escape in springs Of greater less force
the neghborng oucrop elevation Of the group requires
Biologists familiar with this phenomenon and it's ex-
plantation
or transition, underlie this portion of the delta dipping
southwardy from elevation feet above the Gulf and
rupture about the present debouchure Of the
Mississippi river permitting the anes rise 10 auvium and
escape through il to the waters Of the Gulf
this hypothesis be true many these Jets along the bars
Of the get covered and choked with the depostes OF the
river mud and this has great tenacy it's
condition. the dynamic force Of the Artesian spring would
elevate large Of the mud several elevation be-
fore would part sufficiently let the accumulaing waters
escape. is probable, too that many Of these springs inter-
NIT on principles we'll known and If So the island would
gradually sink 10 the level Of its base without the aid
the and currents, which form powerful auxisries
Where deposes occur Of the springs soon establish
their channel of discharge into the Gulf and when this hap
pens The surface the springs visible in the conssn
bubbiog and in the distinct color Of the water am crebly
Informed that get the surface four or sthom
Of water.
These islands bare for years. until the rains wasf
Tout some OF the salt when sodagos aud as,ers and
grasses make their appearance, clothing them with rici
covering Of herbsge.