The times dispatch. [volume] (Richmond, Va.) 1903-1914, 1912-03-17

pounds. It's low heat conductivity
makes 1t valuable ingredient in tho
! manufacture of packing for steam
boilers and pipes, and In the construc-
tion of tlreproof safes. 1t has been
frequently used for the latter pur-
pose. 1t has also been suggested that
| it might be used in certain branches
of the pottery manufacture, which re-
quire on the part OF the materials u
high melting point and the absence
of color.
The green sand marls contain a
considerable amount OF n dark green
mineral known as giauconite, which is
essentially n hydrous silicate of iron
and potash. Where they occur with
AN admixture OF shell mari they may
be worked TO advantage for use as a
fertilizer Such mari contains two
oil the most important constituents in
plant growth. namely. potash and lime.
Mos; of the analyses show n small
percentage OF phosphate of line which
is even more beneficial as plant food.
1t is for this reason that tn: green
sand marls have long been known to
/, he OF value as a natural fcrtilizer.
The mari improves both the chemical
and physical conditions Of the soil
From 90 to 100 bushels per acre
should he used on sandy soil. and from
Besides serving as natural fer
tiliZer. green sand mari which oc-
ours in Underwater Virginia in enorm-
GUS quantity, is now frequently useo
AS base in the manufacture OF arti-
iical fertilizer Most of the green sand
mari now dug in New Jersey aud Vir-
GINA Is being so used. For this pur-
pose the mari is dried pulverized and
then shipped TO fertilizer plants, whcr
other ingredients are added.
Now AS to MARI.
Probably the most important ma
torial included in the mineral re-
sources OF Underwater Virginia is cal
careous. or shell mari. This IS COM
posed In the main of shells of various
sorts. They consist, as is implied by
the name, chiefly of calcium carbon
etc. which. it VIII be remembered. Is
also III main constituent OF lime
stone. Upon tie "ri-:.-..,.on OF suf.i-
aient heat. both shell mari nnd limo
stone can he converted into lime
However. owing to the physical con-
dition of the shell marl, IL is not east
iy burned and can BE- used for ferti-
lizer purposes to better advantage II
1t be ground to n powder to about the
ncness of -four. The mari beds OF
Underwater usually attain considerable
| thickness and thu percentage of lime
in them is very nigh. Analyses OF the
marls generally show n small amount
or potash and phosphoric acid. The
percentage OF lime in the beds de-
Ponds largely upon the amount OF
sand and clay present, forming the
natriX of the beds, as the shells are
composed almost entirely of calcium
carbonate. Some of the narls contain
as much as % per cent. of calcarcous
matter. The Virginia calcareous marls
are found chi fly In the mioccnc group
OF formations and In other places
! Iney arc especially we'll exposed AT
Yorktown. Tho cave In which Corn
wallis took refuge when he was be-
ing corner. ID at Yorktown by Wash
'nEton ana la Fayctte was cut into
one Of these mari beds. The iarg,
areni eNten, and high lime content OF
me shell mari beds render them OF
great commercial value for use in ag-
riculture ana in the manufacture OF
( Portland cement
/ The chief use of mari for agricul-