Written for the Indiana Farmer.
A Course of Chemistry and Geology for
the Practical Farmer.
By Walter May Hew, M. D., Instructor lu  Chemistry, Xew York Preparatory Medical College.
IHE DEVONIAN' ERA.
The Devonian formations extend across
■southern New York, under the Pennsylvania coal measures and reappear in a
limited area of the Mississippi valley.
They comprise sands tones, (the old red
sandstone,) red marls, the characteristic
limestones and shales. In addition to the
lower forms of marine and vegetable life
they contain fossil fishes which are the
distinguishing feature. At the end of this
era a fresh slice of the continent of America has risen from the ocean with projecting peninsulas between which were to lie
the shallow inland seas of the Carboniferous age. Thus we observe the continent
to be gradually extending itself southwards.
The Silurian era included an incredible
number of thousands of years. The Devonian age was certainly shorter but still
dilllcult of computation for the reason
that in many instances vast thicknesses
of its rocks under-went erosion and dissolution.
Relation to  Agriculture.
The rod sandstones and red marls of this
formation frequently give good and desirable land: but when the sandstones are
hard and uniformly silicious the soil is
barren.- The mountain limestone of this
aud the Sub-Carboniferous formations
yield excellent pasturage.
SU1I CABllONIFEHOUS 1'OUMATIONH.
[ Modern geologists have preferred to consider separately the peculiar formations
that aro almost always underneath the
coal measures and when they come to the
surface generally give a more agreeable
aspect to the country. They include
sandstone, shale and various limestones
that make the most valuable of all building material.
THE   CARBONIFEROUS   ERA.    (COAL
MEASURES)
The era that produced the coal measures
whs one in which a low-lying continent
was covered by forests and jungles with
extensive marphy and fresh water areas
The vegetable matter produced in such
abundance would be overflowed and submerged when the burial, exclusion of air
and subsequent pressure caused the partial combustion and transformation. It
was thus the economy of nature filled the
storage cellars of the coal measures. After
submersion in the shallow waters the deposit of a few feet of fresh strata raised
the area out of the water once more, and
the vegetation of a tropical and semi-tropical climate began again, with the production of a fresh coal seam or what
would become such. The chief coal fields
of North America are:
1. Those of the Allegheny range extending to Alabama, 60,000 square miles.
2. Thoso of Illinois and Missouri extending into Indiana and Kentucky on
the one hand, and, to the west, into Iowa,
Minnesota, Kansas, Arkansas and northern Texas, 120,000 square miles.
3. The coal field of Michigan, 5,000
squaie miles.
4. Of I_ode2_land, 500 .square miles.
5. Of Nova Scotia 18,000 square miles.
It must be remembered that in the Rocky
Mountains coal is procured from the  Cre-
tacious and Tertiary strata:
In the coal measures the most usual alternations of layers would include fire
clay, coal, shale, iron ore, limestone and
argilacious shale, and sandstone (mill
stone grit.)
Agriculture.
The sand stonne and mill stone grit of
the coal measures yield barren soil which
can sometimes be improved by adding the
shale that is usually adjacent. The soil
derived from shale would require lime
and draining.
THE JURASSIC AND TRIASSIO ERAS.
These formations in our continent are a
narrow strip reaching with interruptions,
1,000 miles from the Connecticut river
valley to North Carolina. They are mainly
beds of sandstone, including red sandstone, conglomerates with some shales,
beds of clay {Litis,) impure limestones including oolite formed from marine shells,
(freestone).
Upbursts of trap rock are characteristic
of these formations. Such are the Palisades
of the Hudson river. West of the Mississippi those formations cover large areas. In
addition to the lower forms of life the
characteristic fossils are tho remains of
immense reptiles.
-li/WctiM'tre.
The red marls and sandstones of what
is called the new red sandstone or Jurassic
formations form excellent soils all tho
world over. The clays of this formation
are especially intractable. Sometimes a
sandy limestone occurs in close relation
with the clay.
., THE CRETACEOUS ERA.
These formations are named from <•■•_/<.
the I_tln name for chalk, though chalk
The animal remains are those of very
characteristic mollusks or shell fish, reptiles and birds.
Soils upon the chalk are generally un-
productne, but when with the green sand
beds of marl are associated rich in organic
remains containing phosphate of lime a
a marvelous fertility is the result and the
ideal soil for hops. Again, when a Tertiary clay is associated with a chalk, or
chalk and green sand, such a chalk soil is
very prolific. On the Atlantic border and
in Alabama as elsewhere the cffltlk gives a
treeless country lhat bears corn in moderate crops and the hard Georgian wheat.
The scarcity of water which is gotten from
wells which must be bored through the
chalk is unfavorable to small farming.
THE TERTIARY KIIA.
A map of America during this era gives
a continent that dill'ers from that of to-day
only by tho submersion of a fringe along
the Atlantic, south of Martha's Vineyard,
the Mexican (Jnlf including the whole of
Florida. This fringe ascends the Mississippi valley to the mouth of tho Ohio and
there is a narrower fringe along the Pacific coast.   Wo have spoken of that great
PENNSYLVANIA SCENERY—ON RIVER BEI.OW RENOVO.
itself is often absent from the cretaceous
deposits of a whole region. These strata
run along the Atlantic border (covered for
a little distance from the coast by Tertiary
strata), along the north and west of the
Gulf of Mexico, up the Mississippi valley
to the mouth of the Ohio, and from Texas
northward over the slopes of the Rocky
mountains where they have subsequently
been upheaved 12,000 miles above the sea.
Let it be observed that in the America of
the chalk era the Gulf of Mexico was extended as a vast inland sea as far north as
Colorado. The cretaceous rocks are on the
surface in New Jersey and the Southern
Atlantic Statesandin Alabamaand Mississippi. They form also the the Pacific
border and here they are of great thickness
as they are also in California and New
Mexico. These strata contain chalk itself
a very soft carbonate of lime with flints of
ten occurring in it,limestones, shales,sand-
stones of the hard variety, and what is
more characteristic and abundant,sof tsand
beds with clay beds and shell beds that can
be turned up with the pick. These sand beds
are often greenish and are called green
sand. The green sand contains potash
and is quarried as a fertilizer in New Jersey, where it Is improperly called marl.,
prolongation northwards of the Gulf of
Mexico. This during the Tertiary age was
gradually replaced by inland seas and
lakes that formed fresh water Tertiary
deposits comprising among their strata
lignite or brown coal. In the courso of
of this period the Rocky mountains were
upheaved and these strata and those of the
Cretaceous era upturned. The major portion of the Tertiary rocks are not rocks at
all, or are but little consolidated. They
consist of compacted sand, pebbles, etc., or
characteristic clays, but they sometimes
include limestones and the flinty, silicious
buhrstone of Alabama, used for mill
stones.
The Tertiary formations are characterized by the remains of mammals or quadrupeds and such special forms of marine
life as the nummulite so called from its
resemblance to a coin.
Agriculture.
The clays are very intractable aud the
sands are sometimes so unmixed as to be
worthless, but the presence of marls or
limestones may in both cases alter the
prospect. Occasionally in these Tertiary
clays tho presence of organic remains in
nodules called coprolites rich in phosphates makes a small Peru of the region.
I _ST-TERTIARY OR QUATERNARY  ERA.
In this recent age the periods are as follows :
1.    The (Uncial.
During this period estimated by some
geologists as lasting 700,000 years an Arctic -climate prevailed and the action of
glaciers demolished many rocks and transported their debris towards the south.
2. The V/tamplain J'criotl with Lacustrin
formation.
The general level of the continent was
lower than at present and the land was
covered by superficial formations of no
great thickness, by numerous lakes and
rivers.
,'J. The Recent or Alluvial _'_'*'_.
During this period the land has been
raised in terraces visible in river valleys
and along the sea shores. The alluvial deposits correspond strictly to those which
are constantly being formed at all times
by the overflow of rivers and the general
agency of water.
Agriculture.
The (Quaternary deposits enrich the most
prolific agricultural regions of the American continont especially the Mississippi
valley. The fringo that encircles the
southern coast gives at its outer border the
rich soil that grows cotton and rico. Inside the swamp follows a region suitable
for tobacco and sugar.
To be continued.
Commerce, Etc.
It i. an interesting thing right hero,
Mr, 1'resident, bearing upon another
branch of policy that the Senate has
adopted during the present "session, to
notice that, whilo tho discrepancy is most
unfortunately and largely against us in
many countries, in Mexico the showing is
much more favorable, ouroxportsamount-
ing to nearly as much as the imports from
that country, largely because within tho
last few years communication has been
opened and we have been ablo to give to
Mexico a larger proportion of articles in
exchange for hor products than any other
country, and this appears upon tlie necessity, which teems to me goe. as a kindred
measure with this project of reciprocity,
for the passage of tlie bills which my colleague had under his charge, passed
through the Senate some weeks »go, for
extending our communications with these
people. Give us the two togother and it
will inevitably follow that the interchange
of products will advance.
IMPORTS  FROM
Mexico * ll I, (»,__
Central America        .x,]_,<;7l
United states of . oloniMa K ,il7t:VvS
Vene/.ula       71,71-.,-.;. i
lirazii '     .__7,_
Uruguay -      :-, •l.'.M-
Ar-. ntine Republic       . _,'_,7(i.
Chill      15,_,_
1'eru      __._>,'_ I
Cuba     "_,!_,I_
Porto Rico       -in, _,-Jii
Total Imports .I,").7tl 1,7.7
EXPORTS TO
Mexico -. s 1(11,311, .7
Central America  _,(.^l.',.
United States of Colombia  ;Ji,__-,_.l
Vcne.lH-la  '._,.. il,. t
Hrar.il  Kl, l:r_,.V,7
Uruguay  13.011, |_
Argentine Republic  47,_,8I7
t'hili  __,15S,o_
1'eru  7,i.,l,. I i
Cuba  Il_...-,,l7li
Porto Rk-o  1 .Sir,, 1.1
Total exports £   _7,-__)77<; .
Ualam-e against United Slates *1..*_,.-Wl, _l
—From speech of Hon. Kugene Hale, in
United States Senate, September 2.
Tho widest plank on earth is on exhibition at the railroad depot in this city. It
was cut at Klk River mill, and is 1(5 feet in
width. It will bo among the I lumbolt exhibits at the  World's   fair  in   Chicago	
Hunibolts Standard.