Caroline Clifford Newton - "Once Upon A Time In Connecticut"

Annie Besant - "An Introduction to Yoga"

Baroness Orczy - "The League of the Scarlet Pimpernel"

Herbert Jenkins - "The Life of George Borrow"

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




On the surface of the seething lava in the throat of the volcano
there gathers a rock foam, which, when hurled into the air, is
cooled and falls as PUMICE,--a spongy gray rock so light that it
floats on water.

AMYGDULES. The steam blebs of lava flows are often drawn out from
a spherical to an elliptical form resembling that of an almond,
and after the rock has cooled these cavities are gradually filled
with minerals deposited from solution by underground water. From
their shape such casts are called amygdules (Greek, amygdalon, an
almond). Amygdules are commonly composed of silica. Lavas contain
both silica and the alkalies, potash and soda, and after
dissolving the alkalies, percolating water is able to take silica
also into solution. Most AGATES are banded amygdules in which the
silica has been laid in varicolored, concentric layers.

GLASSY AND STONY LAVAS. Volcanic rocks differ in texture according
also to the rate at which they have solidified. When rapidly
cooled, as on the surface of a lava flow, molten rock chills to a
glass, because the minerals of which it is composed have not had
time to separate themselves from the fused mixture and form
crystals. Under slow cooling, as in the interior of the flow, it
becomes a stony mass composed of crystals set in a glassy paste.
In thin slices of volcanic glass one may see under the microscope
the beginnings of crystal growth in filaments and needles and
feathery forms, which are the rudiments of the crystals of various
minerals.

Spherulites, which also mark the first changes of glassy lavas
toward a stony condition, are little balls within the rock,
varying from microscopic size to several inches in diameter, and
made up of radiating fibers.

Perlitic structure, common among glassy lavas, consists of
microscopic curving and interlacing cracks, due to contraction.

FLOW LINES are exhibited by volcanic rocks both to the naked eye
and under the microscope. Steam blebs, together with crystals and
their embryonic forms, are left arranged in lines and streaks by
the currents of the flowing lava as it stiffened into rock.

PORPHYRITIC STRUCTURE. Rocks whose ground mass has scattered
through it large conspicuous crystals are said to be PORPHYRITIC,
and it is especially among volcanic rocks that this structure
occurs. The ground mass of porphyries either may be glassy or may
consist in part of a felt of minute crystals; in either case it
represents the consolidation of the rock after its outpouring upon
the surface. On the other hand, the large crystals of porphyry
have slowly formed deep below the ground at an earlier date.

COLUMNAR STRUCTURE. Just as wet starch contracts on drying to
prismatic forms, so lava often contracts on cooling to a mass of
close-set, prismatic, and commonly six-sided columns, which stand
at right angles to the cooling surface. The upper portion of a
flow, on rapid cooling from the surface exposed to the air, may
contract to a confused mass of small and irregular prisms; while
the remainder forms large and beautifully regular columns, which
have grown upward by slow cooling from beneath.

FRAGMENTAL MATERIALS

Rocks weighing many tons are often thrown from a volcano at the
beginning of an outburst by the breaking up of the solidofied
floor of the crater; and during the progress of an eruption large
blocks may be torn from the throat of the volcano by the outrush
of steam. But the most important fragmental materials are those
derived from the lava itself. As lava rises in the pipe, the steam
which permeates it is released from pressure and explodes, hurling
the lava into the air in fragments of all sizes,--large pieces of
scoria, LAPILLI (fragments the size of a pea or walnut), volcanic
"sand" and volcanic "ashes." The latter resemble in appearance the
ashes of wood or coal, but they are not in any sense, like them, a
residue after combustion.

Volcanic ashes are produced in several ways: lava rising in the
volcanic duct is exploded into fine dust by the steam which
permeates it; glassy lava, hurled into the air and cooled
suddenly, is brought into a state of high strain and tension, and,
like Prince Rupert's drops, flies to pieces at the least
provocation. The clash of rising and falling projectiles also
produces some dust, a fair sample of which may be made by grating
together two pieces of pumice.

Beds of volcanic ash occur widely among recent deposits in the
western United States. In Nebraska ash beds are found in twenty
counties, and are often as white as powdered pumice. The beds grow
thicker and coarser toward the southwestern part of the state,
where their thickness sometimes reaches fifty feet. In what
direction would you look for the now extinct volcano whose
explosive eruptions are thus recorded?

TUFF. This is a convenient term designating any rock composed of
volcanic fragments. Coarse tuffs of angular fragments are called
VOLCANIC BRECIA, and when the fragments have been rounded and
sorted by water the rock is termed a VOLCANIC CONGLOMERATE. Even
when deposited in the open air, as on the slopes of a volcano,
tuffs may be rudely bedded and their fragments more or less
rounded, and unless marine shells or the remains of land plants
and animals are found as fossils in them, there is often
considerable difficulty in telling whether they were laid in water
or in air. In either case they soon become consolidated. Chemical
deposits from percolating waters fill the interstices, and the bed
of loose fragments is cemented to hard rock.

The materials of which tuffs are composed are easily recognized as
volcanic in their origin. The fragments are more or less cellular,
according to the degree to which they were distended with steam
when in a molten state, and even in the finest dust one may see
the glass or the crystals of lava from which it was derived. Tuffs
often contain VOCLANIC BOMBS,--balls of lava which took shape
while whirling in the air, and solidified before falling to the
ground.

ANCIENT VOLCANIC ROCKS. It is in these materials and structures
which we have described that volcanoes leave some of their most
enduring records. Even the volcanic rocks of the earliest geological
ages, uplifted after long burial beneath the sea and exposed to view
by deep erosion, are recognized and their history read despite the
many changes which they may have undergone. A sheet of ancient lava
may be distinguished by its composition from the sediments among
which it is imbedded. The direction of its flow lines may be noted.
The cellular and slaggy surface where the pasty lava was distended
by escaping steam is recognized by the amygdules which now fill the
ancient steam blebs. In a pile of successive sheets of lava each
flow may be distinguished and its thickness measured; for the
surface of each sheet is glassy and scoriaceous, while beneath its
upper portions the lava of each flow is more dense and stony. The
length of time which elapsed before a sheet was buried beneath the
materials of succeeding eruptions may be told by the amount of
weathering which it had undergone, the depth of ancient soil--now
baked to solid rock--upon it, and the erosion which it had suffered
in the interval.

If the flow occurred from some submarine volcano, we may recognize
the fact by the sea-laid sediments which cover it, filling the
cracks and crevices of its upper surface and containing pieces of
lava washed from it in their basal layers.

Long-buried glassy lavas devitrify, or pass to a stony condition,
under the unceasing action of underground waters; but their flow
lines and perlitic and spherulitic structures remain to tell of
their original state.

Ancient tuffs are known by the fragmental character of their
volcanic material, even though they have been altered to firm
rock. Some remains of land animals and plants may be found
imbedded to tell that the beds were laid in open air; while the
remains of marine organisms would prove as surely that the tuffs
were deposited in the sea.

In these ways ancient volcanoes have been recognized near Boston,
in southeastern Pennsylvania, about Lake Superior, and in other
regions of the United States.

THE LIFE HISTORY OF A VOLCANO

The invasion of a region by volcanic forces is attended by
movements of the crust heralded by earthquakes. A fissure or a
pipe is opened and the building of the cone or the spreading of
wide lava sheets is begun.

VOLCANIC CONES. The shape of a volcanic cone depends chiefly on
the materials erupted. Cones made of fragments may have sides as
steep as the angle of repose, which in the case of coarse scoria
is sometimes as high as thirty or forty degrees. About the base of
the mountain the finer materials erupted are spread in more gentle
slopes, and are also washed forward by rains and streams. The
normal profile is thus a symmetric cone with a flaring base.

Cones built of lava vary in form according to the liquidity of the
lava. Domes of gentle slope, as those of Hawaii, for example, are
formed of basalt, which flows to long distances before it
congeals. When superheated and emitted from many vents, this
easily melted lava builds great plateaus, such as that of Iceland.
On the other hand, lavas less fusible, or poured out at a lower
temperature, stiffen when they have flowed but a short distance,
and accumulate in a steep cone. Trachyte has been extruded in a
state so viscid that it has formed steepsided domes like that of
Sarcoui.

Most volcanoes are built, like Vesuvius, both of lava flows and of
tuffs, and sections show that the structure of the cone consists
of outward-dipping, alternating layers of lava, scoria, and ashes.

From time to time the cone is rent by the violence of explosions
and by the weight of the column of lava in the pipe. The fissures
are filled with lava and some discharge on the sides of the
mountain, building parasitic cones, while all form dikes, which
strengthen the pile with ribs of hard rock and make it more
difficult to rend.

Great catastrophes are recorded in the shape of some volcanoes
which consist of a circular rim perhaps miles in diameter,
inclosing a vast crater or a caldera within which small cones may
rise. We may infer that at some time the top of the mountain has
been blown off, or has collapsed and been engulfed because some
reservoir beneath had been emptied by long-continued eruptions.

The cone-building stage may be said to continue until eruptions of
lava and fragmental materials cease altogether. Sooner or later
the volcanic forces shift or die away, and no further eruptions
add to the pile or replace its losses by erosion during periods of
repose. Gases however are still emitted, and, as sulphur vapors
are conspicuous among them, such vents are called SOLFATARAS.
Mount Hood, in Oregon, is an example of a volcano sunk to this
stage. From a steaming rift on its side there rise sulphurous
fumes which, half a mile down the wind, will tarnish a silver
coin.

GEYSERS AND HOT SPRINGS. The hot springs of volcanic regions are
among the last vestiges of volcanic heat. Periodically eruptive
boiling springs are termed geysers. In each of the geyser regions
of the earth--the Yellowstone National Park, Iceland, and New
Zealand--the ground water of the locality is supposed to be heated
by ancient lavas that, because of the poor conductivity of the
rock, still remain hot beneath the surface.

OLD FAITHFUL, one of the many geysers of the Yellowstone National
Park, plays a fountain of boiling water a hundred feet in air;
while clouds of vapor from the escaping steam ascend to several
times that height. The eruptions take place at intervals of from
seventy to ninety minutes. In repose the geyser is a quiet pool,
occupying a craterlike depression in a conical mound some twelve
feet high. The conduit of the spring is too irregular to be
sounded. The mound is composed of porous silica deposited by the
waters of the geyser.

Geysers erupt at intervals instead of continuously boiling,
because their long, narrow, and often tortuous conduits do not
permit a free circulation of the water. After an eruption the tube
is refilled and the water again gradually becomes heated. Deep in
the tube where it is in contact with hot lavas the water sooner or
later reaches the boiling point, and bursting into steam shoots
the water above it high in air.

CARBONATED SPRINGS. After all the other signs of life have gone,
the ancient volcano may emit carbon dioxide as its dying breath.
The springs of the region may long be charged with carbon dioxide,
or carbonated, and where they rise through limestone may be
expected to deposit large quantities of travertine. We should
remember, however, that many carbonated springs, and many hot
springs, are wholly independent of volcanoes.

THE DESTRUCTION OF THE CONE. As soon as the volcanic cone ceases
to grow by eruptions the agents of erosion begin to wear it down,
and the length of time that has elapsed since the period of active
growth may be roughly measured by the degree to which the cone has
been dissected. We infer that Mount Shasta, whose conical shape is
still preserved despite the gullies one thousand feet deep which
trench its sides, is younger than Mount Hood, which erosive
agencies have carved to a pyramidal form. The pile of materials
accumulated about a volcanic vent, no matter how vast in bulk, is
at last swept entirely away. The cone of the volcano, active or
extinct, is not old as the earth counts time; volcanoes are short-
lived geological phenomena.

CRANDALL VOLCANO. This name is given to a dissected ancient
volcano in the Yellowstone National Park, which once, it is
estimated, reared its head thousands of feet above the surrounding
country and greatly exceeded in bulk either Mount Shasta or Mount
Etna. Not a line of the original mountain remains; all has been
swept away by erosion except some four thousand feet of the base
of the pile. This basal wreck now appears as a rugged region about
thirty miles in diameter, trenched by deep valleys and cut into
sharp peaks and precipitous ridges. In the center of the area is
found the nucleus (N, Fig. 237),--a mass of coarsely crystalline
rock that congealed deep in the old volcanic pipe. From it there
radiate in all directions, like the spokes of a wheel, long dikes
whose rock grows rapidly finer of grain as it leaves the vicinity
of the once heated core. The remainder of the base of the ancient
mountain is made of rudely bedded tuffs and volcanic breccia, with
occasional flows of lava, some of the fragments of the breccia
measuring as much as twenty feet in diameter. On the sides of
canyons the breccia is carved by rain erosion to fantastic
pinnacles. At different levels in the midst of these beds of tuff
and lava are many old forest grounds. The stumps and trunks of the
trees, now turned to stone, still in many cases stand upright
where once they grew on the slopes of the mountain as it was
building (Fig. 238). The great size and age of some of these trees
indicate, the lapse of time between the eruption whose lavas or
tuffs weathered to the soil on which they grew and the subsequent
eruption which buried them beneath showers of stones and ashes.

Near the edge of the area lies Death Gulch, in which carbon
dioxide is given off in such quantities that in quiet weather it
accumulates in a heavy layer along the ground and suffocates the
animals which may enter it.





CHAPTER XII

UNDERGROUND STRUCTURES OF IGNEOUS ORIGIN


It is because long-continued erosion lays bare the innermost
anatomy of an extinct volcano, and even sweeps away the entire
pile with much of the underlying strata, thus leaving the very
roots of the volcano open to view, that we are able to study
underground volcanic structures. With these we include, for
convenience, intrusions of molten rock which have been driven
upward into the crust, but which may not have succeeded in
breaking way to the surface and establishing a volcano. All these
structures are built of rock forced when in a fluid or pasty state
into some cavity which it has found or made, and we may classify
them therefore, according to the shape of the molds in which the
molten rock has congealed, as (1) dikes, (2) volcanic necks, (3)
intrusive sheets, and (4) intrusive masses.

DIKES. The sheet of once molten rock with which a fissure has been
filled is known as a dike. Dikes are formed when volcanic cones
are rent by explosions or by the weight of the lava column in the
duct, and on the dissection of the pile they appear as radiating
vertical ribs cutting across the layers of lava and tuff of which
the cone is built. In regions undergoing deformation rocks lying
deep below the ground are often broken and the fissures are filled
with molten rock from beneath, which finds no outlet to the
surface. Such dikes are common in areas of the most ancient rocks,
which have been brought to light by long erosion.

In exceptional cases dikes may reach the length of fifty or one
hundred miles. They vary in width from a fraction of a foot to
even as much as three hundred feet.

Dikes are commonly more fine of grain on the sides than in the
center, and may have a glassy and crackled surface where they meet
the inclosing rock. Can you account for this on any principle
which you have learned?

VOLCANIC NECKS. The pipe of a volcano rises from far below the
base of the cone,--from the deep reservoir from which its
eruptions are supplied. When the volcano has become extinct this
great tube remains filled with hardened lava. It forms a
cylindrical core of solid rock, except for some distance below the
ancient crater, where it may contain a mass of fragments which had
fallen back into the chimney after being hurled into the air.

As the mountain is worn down, this central column known as the
VOLCANIC NECK is left standing as a conical hill (Fig. 240). Even
when every other trace of the volcano has been swept away, erosion
will not have passed below this great stalk on which the volcano
was borne as a fiery flower whose site it remains to mark. In
volcanic regions of deep denudation volcanic necks rise solitary
and abrupt from the surrounding country as dome-shaped hills. They
are marked features in the landscape in parts of Scotland and in
the St. Lawrence valley about Montreal (Fig. 241).

INTRUSIVE SHEETS. Sheets of igneous rocks are sometimes found
interleaved with sedimentary strata, especially in regions where
the rocks have been deformed and have suffered from volcanic
action. In some instances such a sheet is seen to be
CONTEMPORANEOUS (p. 248). In other instances the sheet must be
INTRUSIVE. The overlying stratum, as well as that beneath, has
been affected by the heat of the once molten rock. We infer that
the igneous rock when in a molten state was forced between the
strata, much as a card may be pushed between the leaves of a
closed book. The liquid wedged its way between the layers, lifting
those above to make room for itself. The source of the intrusive
sheet may often be traced to some dike (known therefore as the
FEEDING DIKE), or to some mass of igneous rock.

Intrusive sheets may extend a score and more of miles, and, like
the longest surface flows, the most extensive sheets consist of
the more fusible and fluid lavas,--those of the basic class of
which basalt is an example. Intrusive sheets are usually harder
than the strata in which they lie and are therefore often left in
relief after long denudation of the region (Fig. 315).

On the west bank of the Hudson there extends from New York Bay
north for thirty miles a bold cliff several hundred feet high,--
the PALISADES OF THE HUDSON. It is the outcropping edge of a sheet
of ancient igneous rock, which rests on stratified sandstones and
is overlain by strata of the same series. Sandstones and lava
sheet together dip gently to the west arid the latter disappears
from view two miles back from the river.

It is an interesting question whether the Palisades sheet is
CONTEMPORANEOUS or INTRUSIVE. Was it outpoured on the sandstones
beneath it when they formed the floor of the sea, and covered
forthwith by the sediments of the strata above, or was it intruded
among these beds at a later date?

The latter is the case: for the overlying stratum is intensely
baked along the zone of contact. At the west edge of the sheet is
found the dike in which the lava rose to force its way far and
wide between the strata.

ELECTRIC PEAK, one of the prominent mountains of the Yellowstone
National Park, is carved out of a mass of strata into which many
sheets of molten rock have been intruded. The western summit
consists of such a sheet several hundred feet thick. Studying the
section of Figure 244, what inference do you draw as to the source
of these intrusive sheets?

INTRUSIVE MASSES

BOSSES. This name is generally applied to huge irregular masses of
coarsely crystalline igneous rock lying in the midst of other
formations. Bosses vary greatly in size and may reach scores of
miles in extent. Seldom are there any evidences found that bosses
ever had connection with the surface. On the other hand, it is
often proved that they have been driven, or have melted their way,
upward into the formations in which they lie; for they give off
dikes and intrusive sheets, and have profoundly altered the rocks
about them by their heat.

The texture of the rock of bosses proves that consolidation
proceeded slowly and at great depths, and it is only because of
vast denudation that they are now exposed to view. Bosses are
commonly harder than the rocks about them, and stand up,
therefore, as rounded hills and mountainous ridges long after the
surrounding country has worn to a low plain.

The base of bosses is indefinite or undetermined, and in this
respect they differ from laccoliths. Some bosses have broken and
faulted the overlying beds; some have forced the rocks aside and
melted them away.

The SPANISH PEAKS of southeastern Colorado were formed by the
upthrust of immense masses of igneous rock, bulging and breaking
the overlying strata. On one side of the mountains the throw of
the fault is nearly a mile, and fragments of deep-lying beds were
dragged upward by the rising masses. The adjacent rocks were
altered by heat to a distance of several thousand feet. No
evidence appears that the molten rock ever reached the surface,
and if volcanic eruptions ever took place either in lava flows or
fragmental materials, all traces of them have been effaced. The
rock of the intrusive masses is coarsely crystalline, and no doubt
solidified slowly under the pressure of vast thicknesses of
overlying rock, now mostly removed by erosion.

A magnificent system of dikes radiates from the Peaks to a
distance of fifteen miles, some now being left by long erosion as
walls a hundred feet in height (Fig. 239). Intrusive sheets fed by
the dikes penetrate the surrounding strata, and their edges are
cut by canyons as much as twenty-five miles from the mountain. In
these strata are valuable beds of lignite, an imperfect coal,
which the heat of dikes and sheets has changed to coke.

LACCOLITHS. The laccolith (Greek laccos, cistern; lithos, stone)
is a variety of intrusive masses in which molten rock has spread
between the strata, and, lifting the strata above it to a dome-
shaped form, has collected beneath them in a lens-shaped body with
a flat base.

The HENRY MOUNTAINS, a small group of detached peaks in southern
Utah, rise from a plateau of horizontal rocks. Some of the peaks
are carved wholly in separate domelike uplifts of the strata of
the plateau. In others, as Mount Hillers, the largest of the
group, there is exposed on the summit a core of igneous rock from
which the sedimentary rocks of the flanks dip steeply outward in
all directions. In still others erosion has stripped off the
covering strata and has laid bare the core to its base; and its
shape is here seen to be that of a plano-convex lens or a baker's
bun, its flat base resting on the undisturbed bedded rocks
beneath. The structure of Mount Hillers is shown in Figure 248.
The nucleus of igneous rock is four miles in diameter and more
than a mile in depth.

REGIONAL INTRUSIONS. These vast bodies of igneous rock, which may
reach hundreds of miles in diameter, differ little from bosses
except in their immense bulk. Like bosses, regional intrusions
give off dikes and sheets and greatly change the rocks about them
by their heat. They are now exposed to view only because of the
profound denudation which has removed the upheaved dome of rocks
beneath which they slowly cooled. Such intrusions are accompanied
--whether as cause or as effect is still hardly known--by
deformations, and their masses of igneous rock are thus found as
the core of many great mountain ranges. The granitic masses of
which the Bitter Root Mountains and the Sierra Nevadas have been
largely carved are each more than three hundred miles in length.
Immense regional intrusions, the cores of once lofty mountain
ranges, are found upon the Laurentian peneplain.