The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1885-06-08
MARION COUNTS FORMATION.
The Character of the Several Strata Form
ing the County's Foundation.

DR.. R. T. Brown lectured to the geological
section, some twenty members of the junior
and senior classes of the High school, on Friday,
upon the surface geology and topography of Ma
rion county. Dr. Brown has travelled over every
square mile of the 400 comprising this area. and
the detailed results of his survey are recorded in
the report for 1882
The county, he said is great plain cut from
north to south by the valley of White river.
The average elevation of this plain is It's feet
above low water, and $50 feet above the sea.
This plain rests on three distinct geological
members. The eastern portion of the county
rests the 'corniferous limestone" and the
western portion on the "Genesee shale," the
line separating them passing between this city
and the Hospital for the Insane. Both
of these are Devonian formations
The southwes tern corner of the county, sections
g. 16, 81 and %, lie on the knob sandstone
of the sub-carboniferous for its bedrock. This
'corniferous limestone" which is under the east
half of the county, comes near the surface in
Pogues run and Pleasant run, but is so deep that
quarries can never be proftably worked in
Marion county. The black slate and knobstone
to the west and south of the county is compare
lively worthless as quarry rock or a soil
forming rock, even whereit comes to the surface
But if Marion county has stone quarries it
has something better; it has heavy deposits of
transported material concealing the stratifed
rocks below and upon which the geological inter
est and agricultural value of Marion county de-
pend.
This drift deposit may be studied at the post
Office we'll, at the corner of Pennsylvania and
Market streets. We have here twenty one feet
xvn1 1os1 Ioxrvx kAc>-
come to. the water, then thirtyfve feet
OF gravel with water in it, then eight
feet Of blue clay" then a bed of lower
gravel, thirteen feet, resting the bed
rock. The well is seventy seven feet Deep
and from IL comes the well-known pure water,
free from organic matter. 1t always contains a
solution of the bicarbonate of iron, which is
plainly perceptible to the taste, and tinges red
the vessels which contain it. This is the char
acteristic mark of this lower water wherever
found. The springs of Lawrence give this
water. Also the well known spring on the old
Mcfarland farm, mile southwest of haywood.
The largest of these springs in the county is on
Fielding Beeler's farm, three miles from the
city, near haywood. 1t makes marsh of sew
eral acres, and flows ditch full of water. These
springs are improperly called sulphur springs.
This water is found wherever the blue clay,
which extends as vast sheet from twenty to
one hundred and twenty feet alt over northern
and central Indiana, is tapped by wells or
eroded by streams. The water rises in the
driven wells of the city through tubes to within
twenty -four feet of the surface, and is then read
lily pumped up. Mr.. John Hurry has made a
sanitary analysis of the postofice we'll, and
finds it first class water The blue clay is
twenty five feet thick in the University Park
we'll, nine feet in Circle Park, and sixty feet in
Garfield Park The practical Importance of this
blue clay is that it acts filter, securing
inexhaustable supply of pure water in the layer
of gravel under it. About half the weight of
this blue clay is pure white sand. At the bot
tom of it the remains of cone bearing forest
cypress or hemlock-is often found. In several
of our county wells logs well preserved and fiji
teen inches in diameter have been found, and
they are not broken or crushed, as they would
have been under the weight of an advancing
mountain of ice.
DR.. Brown called the attention of the class to
this blue clay one of the unsolved geological
problems-whether deposited from icebergs,
from still water, or from glaciers. He also spoke
of the upper layers of the drift-the true "oowl
der clay" forty to one hundred feet thick; the
terrace formations of gravel and sand. which
the city is built, and which are fifty to hun
dred feet thick; of the formation of the
rich bottom lands, and of the soil of the county
exclusive of the bottom lands. Our glacial drift
is the potency and pledge of inexhaustable
wealth made by the decomposition of all kinds
of rock, rich in itself porous and absorbent. and
still retaining artificial fertilizers Without this
deposit Marion county would depend upon the
decomposition of the country rock" for its soil,
and in the west and south would be extremely
poor; the east better, as limestones make good
soil when they disntegrate.
The geological and agricultural significance of
the glacial drift was very plainly shown to the
students, and the mutual relations of rock and
soil, and human comfort and progress put in so
interesting and practical way by DR.. Brown
that it made deep impression on the minds Of
the class
Seized a Satchel.