John Lothrop Motley - "History of the United Netherlands, 1584 85"

Sherwood Anderson - "Marching Men"

Compiled and edited by Elias Lönnrot - "The Kalevala"

George Herbert Palmer - "The Nature of Goodness"

New Philadelphia Book Publisher Highlights Local Talent
Book and Publishing News from Publishers Newswire(tm)

Looking for Child to be on Cover of a New Book, 'The Model Child'
PHILADELPHIA, Pa. -- The Philadelphia literary world will celebrate the launch of two new players today, April 10th: Kay Square Press, a new publishing company focused on Philadelphia-area artists, their stories, and their art; and Kay Square's first release, 'With the Rich and Mighty: Emlen Etting of Philadelphia' (ISBN: 978-0-9815129-0-7), a critical biography by Kenneth C. Kaleta.

FlatSigned Press Alleges Don Imus Remarks Damage Legacy of President Gerald R. Ford
NEW YORK, N.Y. -- Nathan Yungerberg, an accomplished model scout and professional child photographer is launching a nation-wide casting call to find the cover model for his highly anticipated book release, 'The Model Child: A Parents Guide to the Child Modeling Industry' (ISBN: 978-0-9817018-0-6).

Books: The Elements of Geology

W >> William Harmon Norton >> The Elements of Geology




Beds of rock salt buried among the strata are dissolved by seeping
water, which issues in salt springs. Gypsum, a mineral composed of
hydrated sulphate of lime, and so soft that it may be scratched
with the finger nail, is readily taken up by water, giving to the
water of wells and springs a peculiar hardness difficult to
remove.

The dissolving action of moisture may be noted on marble
tombstones of some age, marble being a limestone altered by heat
and pressure and composed of crystalline grains. By assuming that
the date on each monument marks the year of its erection, one may
estimate how many years on the average it has taken for weathering
to loosen fine grains on the polished surface, so that they may be
rubbed off with the finger, to destroy the polish, to round the
sharp edges of tool marks in the lettering, and at last to open
cracks and seams and break down the stone. We may notice also
whether the gravestones weather more rapidly on the sunny or the
shady side, and on the sides or on the top.

The weathered surface of granular limestone containing shells
shows them standing in relief. As the shells are made of
crystalline carbonate of lime, we may infer whether the carbonate
of lime is less soluble in its granular or in its crystalline
condition.

THE FORMATION OF CARBONATES. In attacking minerals water does more
than merely take them into solution. It decomposes them, forming
new chemical compounds of which the carbonates are among the most
important. Thus feldspar consists of the insoluble silicate of
alumina, together with certain alkaline silicates which are broken
up by the action of water containing carbon dioxide, forming
alkaline carbonates. These carbonates are freely soluble and
contribute potash and soda to soils and river waters. By the
removal of the soluble ingredients of feldspar there is left the
silicate of alumina, united with water or hydrated, in the
condition of a fine plastic clay which, when white and pure, is
known as KAOLIN and is used in the manufacture of porcelain.
Feldspathic rocks which contain no iron compounds thus weather to
whitish crusts, and even apparently sound crystals of feldspar,
when ground to thin slices and placed under the microscope, may be
seen to be milky in color throughout because an internal change to
kaolin has begun.

OXIDATION. Rocks containing compounds of iron weather to reddish
crusts, and the seams of these rocks are often lined with rusty
films. Oxygen and water have here united with the iron, forming
hydrated iron oxide. The effects of oxidation may be seen in the
alteration of many kinds of rocks and in red and yellow colors of
soils and subsoils.

Pyrite is a very hard mineral of a pale brass color, found in
scattered crystals in many rocks, and is composed of iron and
sulphur (iron sulphide). Under the attack of the weather it takes
up oxygen, forming iron sulphate (green vitriol), a soluble
compound, and insoluble hydrated iron oxide, which as a mineral is
known as limonite. Several large masses of iron sulphide were
placed some years ago on the lawn in front of the National Museum
at Washington. The mineral changed so rapidly to green vitriol
that enough of this poisonous compound was washed into the ground
to kill the roots of the surrounding grass.

AGENTS OF MECHANICAL DISINTEGRATION

HEAT AND COLD. Rocks exposed to the direct rays of the sun become
strongly heated by day and expand. After sunset they rapidly cool
and contract. When the difference in temperature between day and
night is considerable, the repeated strains of sudden expansion
and contraction at last become greater than the rocks can bear,
and they break, for the same reason that a glass cracks when
plunged into boiling water (Fig. 5).

Rocks are poor conductors of heat, and hence their surfaces may
become painfully hot under the full blaze of the sun, while the
interior remains comparatively cool. By day the surface shell
expands and tends to break loose from the mass of the stone. In
cooling in the evening the surface shell suddenly contracts on the
unyielding interior and in time is forced off in scales.

Many rocks, such as granite, are made up of grains of various
minerals which differ in color and in their capacity to absorb
heat, and which therefore contract and expand in different ratios.
In heating and cooling these grains crowd against their neighbors
and tear loose from them, so that finally the rock disintegrates
into sand.

The conditions for the destructive action of heat and cold are
most fully met in arid regions when vegetation is wanting for lack
of sufficient rain. The soil not being held together by the roots
of plants is blown away over large areas, leaving the rocks bare
to the blazing sun in a cloudless sky. The air is dry, and the
heat received by the earth by day is therefore rapidly radiated at
night into space. There is a sharp and sudden fall of temperature
after sunset, and the rocks, strongly heated by day, are now
chilled perhaps even to the freezing point.

In the Sahara the thermometer has been known to fall 131 degrees
F. within a few hours. In the light air of the Pamir plateau in
central Asia a rise of 90 degrees F. has been recorded from seven
o'clock in the morning to one o'clock in the afternoon. On the
mountains of southwestern Texas there are frequently heard
crackling noises as the rocks of that arid region throw off scales
from a fraction of an inch to four inches in thickness, and loud
reports are made as huge bowlders split apart. Desert pebbles
weakened by long exposure to heat and cold have been shivered to
fine sharp-pointed fragments on being placed in sand heated to 180
degrees F. Beds half a foot thick, forming the floor of limestone
quarries in Wisconsin, have been known to buckle and arch and
break to fragments under the heat of the summer sun.

FROST. By this term is meant the freezing and thawing of water
contained in the pores and crevices of rocks. All rocks are more
or less porous and all contain more or less water in their pores.
Workers in stone call this "quarry water," and speak of a stone as
"green" before the quarry water has dried out. Water also seeps
along joints and bedding planes and gathers in all seams and
crevices. Water expands in freezing, ten cubic inches of water
freezing to about eleven cubic inches of ice. As water freezes in
the rifts and pores of rocks it expands with the irresistible
force illustrated in the freezing and breaking of water pipes in
winter. The first rift in the rock, perhaps too narrow to be seen,
is widened little by little by the wedges of successive frosts,
and finally the rock is broken into detached blocks, and these
into angular chip-stone by the same process.

It is on mountain tops and in high latitudes that the effects of
frost are most plainly seen. "Every summit" says Whymper, "amongst
the rock summits upon which I have stood has been nothing but a
piled-up heap of fragments" (Fig. 7). In Iceland, in Spitsbergen,
in Kamchatka, and in other frigid lands large areas are thickly
strewn with sharp-edged fragments into which the rock has been
shattered by frost.

ORGANIC AGENTS

We must reckon the roots of plants and trees among the agents
which break rocks into pieces. The tiny rootlet in its search for
food and moisture inserts itself into some minute rift, and as it
grows slowly wedges the rock apart. Moreover, the acids of the
root corrode the rocks with which they are in contact. One may
sometimes find in the soil a block of limestone wrapped in a mesh
of roots, each of which lies in a little furrow where it has eaten
into the stone.

Rootless plants called lichens often cover and corrode rocks as
yet bare of soil; but where lichens are destroying the rock less
rapidly than does the weather, they serve in a way as a
protection.

CONDITIONS FAVORING DISINTEGRATION AND DECAY. The
disintegration of rocks under frost and temperature changes
goes on most rapidly in cold and arid climates, and where
vegetation is scant or absent. On the contrary, the decay of rocks
under the chemical action of water is favored by a warm, moist
climate and abundant vegetation. Frost and heat and cold can only
act within the few feet from the surface to which the necessary
temperature changes are limited, while water penetrates and alters
the rocks to great depths.

The pupil may explain.

In what ways the presence of joints and bedding planes assists in
the breaking up and decay of rocks under the action of the
weather.

Why it is a good rule of stone masons never to lay stones on edge,
but always on their natural bedding planes.

Why stones fresh from the quarry sometimes go to pieces in early
winter, when stones which have been quarried for some months
remain uninjured.

Why quarrymen in the northern states often keep their quarry
floors flooded during winter.

Why laminated limestone should not be used for curbstone.

Why rocks composed of layers differing in fineness of grain and in
ratios of expansion do not make good building stone.

Fine-grained rocks with pores so small that capillary attraction
keeps the water which they contain from readily draining away are
more apt to hold their pores ten elevenths full of water than are
rocks whose pores are larger. Which, therefore, are more likely to
be injured by frost?

Which is subject to greater temperature changes, a dark rock or
one of a light color? the north side or the south side of a
valley?

THE MANTLE OF ROCK WASTE

We have seen that rocks are everywhere slowly wasting away. They
are broken in pieces by frost, by tree roots, and by heat and
cold. They dissolve and decompose under the chemical action of
water and the various corrosive substances which it contains,
leaving their insoluble residues as residual clays and sands upon
the surface. As a result there is everywhere forming a mantle of
rock waste which covers the land. It is well to imagine how the
country would appear were this mantle with its soil and vegetation
all scraped away or had it never been formed. The surface of the
land would then be everywhere of bare rock as unbroken as a quarry
floor.

THE THICKNESS OF THE MANTLE. In any locality the thickness of the
mantle of rock waste depends as much on the rate at which it is
constantly being removed as on the rate at which it is forming. On
the face of cliffs it is absent, for here waste is removed as fast
as it is made. Where waste is carried away more slowly than it is
produced, it accumulates in time to great depth.

The granite of Pikes Peak is disintegrated to a depth of twenty
feet. In the city of Washington granite rock is so softened to a
depth of eighty feet that it can be removed with pick and shovel.
About Atlanta, Georgia, the rocks are completely rotted for one
hundred feet from the surface, while the beginnings of decay may
be noticed at thrice that depth. In places in southern Brazil the
rock is decomposed to a depth of four hundred feet.

In southwestern Wisconsin a reddish residual clay has an average
depth of thirteen feet on broad uplands, where it has been removed
to the least extent. The country rock on which it rests is a
limestone with about ten per cent of insoluble impurities. At
least how thick, then, was that portion of the limestone which has
rotted down to the clay?

DISTINGUISHING CHARACTERISTICS OF RESIDUAL WASTE. We must learn to
distinguish waste formed in place by the action of the weather
from the products of other geological agencies. Residual waste is
unstratified. It contains no substances which have not been
derived from the weathering of the parent rock. There is a gradual
transition from residual waste into the unweathered rock beneath.
Waste resting on sound rock evidently has been shifted and was not
formed in place.

In certain regions of southern Missouri the land is covered with a
layer of broken flints and red clay, while the country rock is
limestone. The limestone contains nodules of flint, and we may
infer that it has been by the decay and removal of thick masses of
limestone that the residual layer of clay and flints has been left
upon the surface. Flint is a form of quartz, dull-lustered,
usually gray or blackish in color, and opaque except on thinnest
edges, where it is translucent.

Over much of the northern states there is spread an unstratified
stony clay called the drift. It often rests on sound rocks. It
contains grains of sand, pebbles, and bowlders composed of many
different minerals and rocks that the country rock cannot furnish.
Hence the drift cannot have been formed by the decay of the rock
of the region. A shale or limestone, for example, cannot waste to
a clay containing granite pebbles. The origin of the drift will be
explained in subsequent chapters.

The differences in rocks are due more to their soluble than to
their insoluble constituents. The latter are few in number and are
much the same in rocks of widely different nature, being chiefly
quartz, silicate of alumina, and iron oxide. By the removal of
their soluble parts very many and widely different rocks rot down
to a residual clay gritty with particles of quartz and colored red
or yellow with iron oxide.

In a broad way the changes which rocks undergo in weathering are
an adaptation to the environment in which they find themselves at
the earth's surface,--an environment different from that in which
they were formed under sea or under ground. In open air, where
they are attacked by various destructive agents, few of the rock-
making minerals are stable compounds except quartz, the iron
oxides, and the silicate of alumina; and so it is to one or more
of these comparatively insoluble substances that most rocks are
reduced by long decay.

Which produces a mantle of finer waste, frost or chemical decay?
which a thicker mantle? In what respects would you expect that the
mantle of waste would differ in warm humid lands like India, in
frozen countries like Alaska, and in deserts such as the Sahara?

THE SOIL. The same agencies which produce the mantle of waste are
continually at work upon it, breaking it up into finer and finer
particles and causing its more complete decay. Thus on the
surface, where the waste has weathered longest, it is gradually
made fine enough to support the growth of plants, and is then
known as soil. The coarser waste beneath is sometimes spoken of as
subsoil. Soil usually contains more or less dark, carbonaceous,
decaying organic matter, called humus, and is then often termed
the humus layer. Soil forms not only on waste produced in place
from the rock beneath, but also on materials which have been
transported, such as sheets of glacial drift and river deposits.
Until rocks are reduced to residual clays the work of the weather
is more rapid and effective on the fragments of the mantle of
waste than on the rocks from which waste is being formed. Why?

Any fresh excavation of cellar or cistern, or cut for road or
railway, will show the characteristics of the humus layer. It may
form only a gray film on the surface, or we may find it a layer a
foot or more thick, dark, or even black, above, and growing
gradually lighter in color as it passes by insensible gradations
into the subsoil. In some way the decaying vegetable matter
continually forming on the surface has become mingled with the
material beneath it.

HOW HUMUS AND THE SUBSOIL ARE MINGLED. The mingling of humus and
the subsoil is brought about by several means. The roots of plants
penetrate the waste, and when they die leave their decaying
substance to fertilize it. Leaves and stems falling on the surface
are turned under by several agents. Earthworms and other animals
whose home is in the waste drag them into their burrows either for
food or to line their nests. Trees overthrown by the wind, roots
and all, turn over the soil and subsoil and mingle them together.
Bacteria also work in the waste and contribute to its enrichment.
The animals living in the mantle do much in other ways toward the
making of soil. They bring the coarser fragments from beneath to
the surface, where the waste weathers more rapidly. Their burrows
allow air and water to penetrate the waste more freely and to
affect it to greater depths.

ANTS. In the tropics the mantle of waste is worked over chiefly by
ants. They excavate underground galleries and chambers, extending
sometimes as much as fourteen feet below the surface, and build
mounds which may reach as high above it. In some parts of Paraguay
and southern Brazil these mounds, like gigantic potato hills,
cover tracts of considerable area.

In search for its food--the dead wood of trees--the so-called
white ant constructs runways of earth about the size of gas pipes,
reaching from the base of the tree to the topmost branches. On the
plateaus of central Africa explorers have walked for miles through
forests every tree of which was plastered with these galleries of
mud. Each grain of earth used in their construction is moistened
and cemented by slime as it is laid in place by the ant, and is
thus acted on by organic chemical agents. Sooner or later these
galleries are beaten down by heavy rains, and their fertilizing
substances are scattered widely by the winds.

EARTHWORMS. In temperate regions the waste is worked over largely
by earthworms. In making their burrows worms swallow earth in
order to extract from it any nutritive organic matter which it may
contain. They treat it with their digestive acids, grind it in
their stony gizzards, and void it in castings on the surface of
the ground. It was estimated by Darwin that in many parts of
England each year, on every acre, more than ten tons of earth pass
through the bodies of earthworms and are brought to the surface,
and that every few years the entire soil layer is thus worked over
by them.

In all these ways the waste is made fine and stirred and enriched.
Grain by grain the subsoil with its fresh mineral ingredients is
brought to the surface, and the rich organic matter which plants
and animals have taken from the atmosphere is plowed under. Thus
Nature plows and harrows on "the great world's farm" to make ready
and ever to renew a soil fit for the endless succession of her
crops.

The world processes by which rocks are continually wasting away
are thus indispensable to the life of plants and animals. The
organic world is built on the ruins of the inorganic, and because
the solid rocks have been broken down into soil men are able to
live upon the earth.

SOLAR ENERGY. The source of the energy which accomplishes all this
necessary work is the sun. It is the radiant energy of the sun
which causes the disintegration of rocks, which lifts vapor into
the atmosphere to fall as rain, which gives life to plants and
animals. Considering the earth in a broad way, we may view it as a
globe of solid rock,--the lithosphere,--surrounded by two mobile
envelopes: the envelope of air,--THE ATMOSPHERE, and the envelope
of water,--THE HYDROSPHERE. Under the action of solar energy these
envelopes are in constant motion. Water from the hydrosphere is
continually rising in vapor into the atmosphere, the air of the
atmosphere penetrates the hydrosphere,--for its gases are
dissolved in all waters,--and both air and water enter and work
upon the solid earth. By their action upon the lithosphere they
have produced a third envelope,--the mantle of rock waste.

This envelope also is in movement, not indeed as a whole, but
particle by particle. The causes which set its particles in
motion, and the different forms which the mantle comes to assume,
we will now proceed to study.

MOVEMENTS OF THE MANTLE OF ROCK WASTE

At the sandstone ledges which we first visited we saw not only
that the rocks were crumbling away, but also that grains and
fragments of them were creeping down the slopes of the valley to
the stream and were carried by it onward toward the sea. This
process is going on everywhere. Slowly it may be, and with many
interruptions, but surely, the waste of the land moves downward to
the sea. We may divide its course into two parts,--the path to the
stream, which we will now consider, and its carriage onward by the
stream, which we will defer to a later chapter.

GRAVITY. The chief agent concerned in the movement of waste is
gravity. Each particle of waste feels the unceasing downward pull
of the earth's mass and follows it when free to do so. All
agencies which produce waste tend to set its particles free and in
motion, and therefore cooperate with gravity. On cliffs, rocks
fall when wedged off by frost or by roots of trees, and when
detached by any other agency. On slopes of waste, water freezes in
chinks between stones, and in pores between particles of soil, and
wedges them apart. Animals and plants stir the waste, heat expands
it, cold contracts it, the strokes of the raindrops drive loose
particles down the slope and the wind lifts and lets them fall. Of
all these movements, gravity assists those which are downhill and
retards those which are uphill. On the whole, therefore, the
downhill movements prevail, and the mantle of waste, block by
block and grain by grain, creeps along the downhill path.

A slab of sandstone laid on another of the same kind at an angle
of 17 degrees and left in the open air was found to creep down the
slope at the rate of a little more than a millimeter a month.
Explain why it did so.

RAIN. The most efficient agent in the carriage of waste to the
streams is the rain. It moves particles of soil by the force of
the blows of the falling drops, and washes them down all slopes to
within reach of permanent streams. On surfaces unprotected by
vegetation, as on plowed fields and in arid regions, the rain
wears furrows and gullies both in the mantle of waste and in
exposures of unaltered rock (Fig. 17).

At the foot of a hill we may find that the soil has accumulated by
creep and wash to the depth of several feet; while where the
hillside is steepest the soil may be exceedingly thin, or quite
absent, because removed about as fast as formed. Against the walls
of an abbey built on a slope in Wales seven hundred years ago, the
creeping waste has gathered on the uphill side to a depth of seven
feet. The slow-flowing sheet of waste is often dammed by fences
and walls, whose uphill side gathers waste in a few years so as to
show a distinctly higher surface than the downhill side,
especially in plowed fields where the movement is least checked by
vegetation.

TALUS. At the foot of cliffs there is usually to be found a slope
of rock fragments which clearly have fallen from above. Such a
heap of waste is known as talus. The amount of talus in any place
depends both on the rate of its formation and the rate of its
removal. Talus forms rapidly in climates where mechanical
disintegration is most effective, where rocks are readily broken
into blocks because closely jointed and thinly bedded rather than
massive, and where they are firm enough to be detached in
fragments of some size instead of in fine grains. Talus is removed
slowly where it decays slowly, either because of the climate or
the resistance of the rock. It may be rapidly removed by a stream
flowing along its base.

In a moist climate a soluble rock, such as massive limestone, may
form talus little if any faster than the talus weathers away. A
loose-textured sandstone breaks down into incoherent sand grains,
which in dry climates, where unprotected by vegetation, may be
blown away as fast as they fall, leaving the cliff bare to the
base. Cliffs of such slow-decaying rocks as quartzite and granite
when closely jointed accumulate talus in large amounts.

Talus slopes may be so steep as to reach THE ANGLE OF REPOSE, i.e.
the steepest angle at which the material will lie. This angle
varies with different materials, being greater with coarse and
angular fragments than with fine rounded grains. Sooner or later a
talus reaches that equilibrium where the amount removed from its
surface just equals that supplied from the cliff above. As the
talus is removed and weathers away its slope retreats together
with the retreat of the cliff, as seen in Figure 9.

GRADED SLOPES. Where rocks weather faster than their waste is
carried away, the waste comes at last to cover all rocky ledges.
On the steeper slopes it is coarser and in more rapid movement
than on slopes more gentle, but mountain sides and hills and
plains alike come to be mantled with sheets of waste which
everywhere is creeping toward the streams. Such unbroken slopes,
worn or built to the least inclination at which the waste supplied
by weathering can be urged onward, are known as GRADED SLOPES.

Of far less importance than the silent, gradual creep of waste,
which is going on at all times everywhere about us, are the
startling local and spasmodic movements which we are now to
describe.

AVALANCHES. On steep mountain sides the accumulated snows of
winter often slip and slide in avalanches to the valleys below.
These rushing torrents of snow sweep their tracks clean of waste
and are one of Nature's normal methods of moving it along the
downhill path.