MINERAL VEINS.
Werner's doctrine that mineral veins were fissures filled from
above--Veins of segregation--Ordinary metalliferous veins or
lodes--Their frequent coincidence with faults--Proofs that they
originated in fissures in solid rock--Veins shifting other
veins--Polishing of their walls--Shells and pebbles in lodes--Evidence
of the successive enlargement and re-opening of veins--Fournet's
observations in Auvergne--Dimensions of veins--Why some alternately
swell out and contract--Filling of lodes by sublimation from
below--Chemical and electrical action--Relative age of the precious
metals--Copper and lead veins in Ireland older than Cornish tin--Lead
vein in lias, Glamorganshire--Gold in Russia--Connection of hot
springs and mineral veins--Concluding remarks.
The manner in which metallic substances are distributed through the earth's
crust, and more especially the phenomena of those nearly vertical and
tabular masses of ore called mineral veins, from which the larger part of
the precious metals used by man are obtained,--these are subjects of the
highest practical importance to the miner, and of no less theoretical
interest to the geologist.
The views entertained respecting metalliferous veins have been modified,
or, rather, have undergone an almost complete revolution, since the middle
of the last century, when Werner, as director of the School of Mines, at
Freiberg in Saxony, first attempted to generalize the facts then known. He
taught that mineral veins had originally been open fissures which were
gradually filled up with crystalline and metallic matter, and that many of
them, after being once filled, had been again enlarged or re-opened. He
also pointed out that veins thus formed are not all referable to one era,
but are of various geological dates.
Such opinions, although slightly hinted at by earlier writers, had never
before been generally received, and their announcement by one of high
authority and great experience constituted an era in the science.
Nevertheless, I have shown, when tracing, in another work, the history and
progress of geology, that Werner was far behind some of his predecessors in
his theory of the volcanic rocks, and less enlightened than his
contemporary, Dr. Hutton, in his speculations as to the origin of
granite.[489-A] According to him, the plutonic formations, as well as the
crystalline schists, were substances precipitated from a chaotic fluid in
some primeval or nascent condition of the planet; and the metals,
therefore, being closely connected with them, had partaken, according to
him, of a like mysterious origin. He also held that the trap rocks were
aqueous deposits, and that dikes of porphyry, greenstone, and basalt, were
fissures filled with their several contents from above. Hence he naturally
inferred that mineral veins had derived their component materials from an
incumbent ocean, rather than from a subterranean source; that these
materials had been first dissolved in the waters above, instead of having
risen up by sublimation from lakes and seas of igneous matter below.
In proportion as the hypothesis of a primeval fluid, or "chaotic
menstruum," was abandoned, in reference to the plutonic formations, and
when all geologists had come to be of one mind as to the true relation of
the volcanic and trappean rocks, reasonable hopes began to be entertained
that the phenomena of mineral veins might be explained by known causes, or
by chemical, thermal, and electrical agency still at work in the interior
of the earth. The grounds of this conclusion will be better understood when
the geological facts brought to light by mining operations have been
described and explained.
_On different kinds of mineral veins._--Every geologist is familiarly
acquainted with those veins of quartz which abound in hypogene strata,
forming lenticular masses of limited extent. They are sometimes observed,
also, in sandstones and shales. Veins of carbonate of lime are equally
common in fossiliferous rocks, especially in limestones. Such veins appear
to have once been chinks or small cavities, caused, like cracks in clay, by
the shrinking of the mass, which has consolidated from a fluid state, or
has simply contracted its dimensions in passing from a higher to a lower
temperature. Siliceous, calcareous, and occasionally metallic matters, have
sometimes found their way simultaneously into such empty spaces, by
infiltration from the surrounding rocks, or by segregation, as it is often
termed. Mixed with hot water and steam, metallic ores may have permeated a
pasty matrix until they reached those receptacles formed by shrinkage, and
thus gave rise to that irregular assemblage of veins, called by the Germans
a "stockwerk," in allusion to the different floors on which the mining
operations are in such cases carried on.
The more ordinary or regular veins are usually worked in vertical shafts,
and have evidently been fissures produced by mechanical violence. They
traverse all kinds of rocks, both hypogene and fossiliferous, and extend
downwards to indefinite or unknown depths. We may assume that they
correspond with such rents as we see caused from time to time by the shock
of an earthquake. Metalliferous veins, referable to such agency, are
occasionally a few inches wide, but more commonly 3 or 4 feet. They hold
their course continuously in a certain prevailing direction for miles or
leagues, passing through rocks varying in mineral composition.
[3 Illustrations: Fig. 513. Fig. 514. Fig. 515. Vertical sections of the
mine of Huel Peever, Redruth, Cornwall.]
_That metalliferous veins were fissures._--As some intelligent miners,
after an attentive study of metalliferous veins, have been unable to
reconcile many of their characteristics with the hypothesis of fissures, I
shall begin by stating the evidence in its favour. The most striking fact
perhaps which can be adduced in its support is, the coincidence of a
considerable proportion of mineral veins with _faults_, or those
dislocations of rocks which are indisputably due to mechanical force, as
above explained (p. 62.). There are even proofs in almost every mining
district of a succession of faults, by which the opposite walls of rents,
now the receptacles of metallic substances, have suffered displacement.
Thus, for example, suppose _a a_, fig. 513., to be a tin lode in Cornwall,
the term _lode_ being applied to veins containing metallic ores. This lode,
running east and west, is a yard wide, and is shifted by a copper lode (_b
b_), of similar width.
The first fissure (_a a_) has been filled with various materials, partly
of chemical origin, such as quartz, fluor-spar, peroxide of tin,
sulphuret of copper, arsenical pyrites, bismuth, and sulphuret of
nickel, and partly of mechanical origin, comprising clay and angular
fragments or detritus of the intersected rocks. The plates of quartz and
the ores are, in some places, parallel to the vertical sides or walls of
the vein, being divided from each other by alternating layers of clay,
or other earthy matter. Occasionally the metallic ores are disseminated
in detached masses among the veinstones.
It is clear that, after the gradual introduction of the tin and other
substances, the second rent (_b b_) was produced by another fracture
accompanied by a displacement of the rocks along the plane of _b b_. This
new opening was then filled with minerals, some of them resembling those in
_a a_, as fluor-spar (or fluate of lime) and quartz; others different, the
copper being plentiful and the tin wanting or very scarce.
We must next suppose the shock of a third earthquake to occur, breaking
asunder all the rocks along the line c _c_, fig. 514.; the fissure in this
instance, being only 6 inches wide, and simply filled with clay, derived,
probably, from the friction of the walls of the rent, or partly, perhaps,
washed in from above. This new movement has heaved the rock in such a
manner as to interrupt the continuity of the copper vein (_b b_), and, at
the same time, to shift or heave laterally in the same direction a portion
of the tin vein which had not previously been broken.
Again, in fig. 515. we see evidence of a fourth fissure (_d d_), also
filled with clay, which has cut through the tin vein (_a a_), and has
lifted it slightly upwards towards the south. The various changes here
represented are not ideal, but are exhibited in a section obtained in
working an old Cornish mine, long since abandoned, in the parish of
Redruth, called Huel Peever, and described both by Mr. Williams and Mr.
Carne.[491-A] The principal movement here referred to, or that of _c c_,
fig. 515., extends through a space of no less than 84 feet; but in this, as
in the case of the other three, it will be seen that the outline of the
country above, or the geographical features of Cornwall, are not affected
by any of the dislocations, a powerful denuding force having clearly been
exerted subsequently to all the faults. (See above, p. 69.) It is commonly
said in Cornwall, that there are eight distinct systems of veins which can
in like manner be referred to as many successive movements or fractures;
and the German miners of the Hartz Mountains speak also of eight systems of
veins, referable to as many periods.
Besides the proofs of mechanical action already explained, the opposite
walls of veins are frequently polished and striated, as if they had
undergone great friction, and this even in cases where there has been no
shift. We may attribute such rubbing to a vibratory motion known to
accompany earthquakes, and to produce trituration on the opposite walls of
rents. Similar movements have sometimes occurred in mineral veins which
had been wholly or partially filled up; for included pieces of rock,
detached from the sides, are found to be rounded, polished, and striated.
That a great many veins communicated originally with the surface of the
country above, or with the bed of the sea, is proved by the occurrence
in them of well rounded pebbles, agreeing with those in superficial
alluviums, as in Auvergne and Saxony. In Bohemia, such pebbles have been
met with at the depth of 180 fathoms. In Cornwall, Mr. Carne mentions
true pebbles of quartz and slate in a tin lode of the Relistran Mine, at
the depth of 600 feet below the surface. They were cemented by oxide of
tin and bisulphuret of copper, and were traced over a space more than 12
feet long and as many wide.[492-A] Marine fossil shells, also, have been
found at great depths, having probably been engulphed during submarine
earthquakes. Thus, a gryphaea is stated by M. Virlet to have been met
with in a lead-mine near Semur, in France, and a madrepore in a compact
vein of cinnabar in Hungary.[492-B]
When different sets or systems of veins occur in the same country, those
which are supposed to be of contemporaneous origin, and which are filled
with the same kind of metals, often maintain a general parallelism of
direction. Thus, for example, both the tin and copper veins in Cornwall run
nearly east and west, while the lead-veins run north and south; but there
is no general law of direction common to different mining districts. The
parallelism of the veins is another reason for regarding them as ordinary
fissures, for we observe that contemporaneous trap dikes, admitted by all
to be masses of melted matter which have filled rents, are often parallel.
Assuming, then, that veins are simply fissures in which chemical and
mechanical deposits have accumulated, we may next consider the proofs of
their having been filled gradually and often during successive
enlargements. I have already spoken of parallel layers of clay, quartz, and
ore. Werner himself observed, in a vein near Gersdorff, in Saxony, no less
than thirteen beds of different minerals, arranged with the utmost
regularity on each side of the central layer. This layer was formed of two
beds of calcareous spar, which had evidently lined the opposite walls of a
vertical cavity. The thirteen beds followed each other in corresponding
order, consisting of fluor-spar, heavy spar, galena, &c. In these cases,
the central mass has been last formed, and the two plates which coat the
outer walls of the rent on each side are the oldest of all. If they consist
of crystalline precipitates, they may be explained by supposing the fissure
to have remained unaltered in its dimensions, while a series of changes
occurred in the nature of the solutions which rose up from below; but such
a mode of deposition, in the case of many successive and parallel layers,
appears to be exceptional.
If a veinstone consist of crystalline matter, the points of the crystals
are always turned inwards, or towards the centre of the vein; in other
words, they point in that direction where there was most space for the
development of the crystals. Thus each new layer receives the impression of
the crystals of the preceding layer, and imprints its crystals on the one
which follows, until at length the whole of the vein is filled: the two
layers which meet dovetail the points of their crystals the one into the
other. But in Cornwall, some lodes occur where the vertical plates, or
_combs_, as they are there called, exhibit crystals so dovetailed as to
prove that the same fissure has been often enlarged. Sir H. De la Beche
gives the following curious and instructive example (fig. 516.) from a
copper-mine in granite, near Redruth.[493-A] Each of the plates or combs
(_a_, _b_, _c_, _d_, _e_, _f_) are double, having the points of their
crystals turned inwards along the axis of the comb. The sides or walls (2,
3, 4, 5, and 6) are parted by a thin covering of ochreous clay, so that
each comb is readily separable from another by a moderate blow of the
hammer. The breadth of each represents the whole width of the fissure at
six successive periods, and the outer walls of the vein, where the first
narrow rent was formed, consisted of the granitic surfaces 1 and 7.
[Illustration: Fig. 516. Copper lode, near Redruth, enlarged at
six successive periods.]
A somewhat analogous interpretation is applicable to numbers of other
cases, where clay, sand, or angular detritus, alternate with ores and
veinstones. Thus, we may imagine the sides of a fissure to be encrusted
with siliceous matter, as Von Buch observed, in Lancerote, the walls of
a volcanic crater formed in 1731 to be traversed by an open rent in
which hot vapours had deposited hydrate of silica, the incrustation
nearly extending to the middle.[493-B] Such a vein may then be filled
with clay or sand, and afterwards re-opened, the new rent dividing the
argillaceous deposit, and allowing a quantity of rubbish to fall down.
Various metals and spars may then be precipitated from aqueous solutions
among the interstices of this heterogeneous mass.
That such changes have repeatedly occurred, is demonstrated by
occasional cross-veins, implying the oblique fracture of previously
formed chemical and mechanical deposits. Thus, for example, M. Fournet,
in his description of some mines in Auvergne worked under his
superintendence, observes, that the granite of that country was first
penetrated by veins of granite, and then dislocated, so that open rents
crossed both the granite and the granitic veins. Into such openings,
quartz, accompanied by sulphurets of iron and arsenical pyrites, was
introduced. Another convulsion then burst open the rocks along the old
line of fracture, and the first set of deposits were cracked and often
shattered, so that the new rent was filled, not only with angular
fragments of the adjoining rocks, but with pieces of the older
veinstones. Polished and striated surfaces on the sides or in the
contents of the vein also attest the reality of these movements. A new
period of repose then ensued, during which various sulphurets were
introduced, together with hornstone quartz, by which angular fragments
of the older quartz before mentioned were cemented into a breccia. This
period was followed by other dilatations of the same veins, and other
sets of mineral deposits, until, at last, pebbles of the basaltic lavas
of Auvergne, derived from superficial alluviums, probably of Miocene or
older Pliocene date, were swept into the veins. I have not space to
enumerate all the changes minutely detailed by M. Fournet, but they are
valuable, both to the miner and geologist, as showing how the supposed
signs of violent catastrophes may be the monuments, not of one
paroxysmal shock, but of reiterated movements.
Such repeated enlargement and re-opening of veins might have been
anticipated, if we adopt the theory of fissures, and reflect how few of
them have ever been sealed up entirely, and that a country with fissures
only partially filled must naturally offer much feebler resistance along
the old lines of fracture than any where else. It is quite otherwise in the
case of dikes, where each opening has been the receptacle of one continuous
and homogeneous mass of melted matter, the consolidation of which has taken
place under considerable pressure. Trappean dikes can rarely fail to
strengthen the rocks at the points where before they were weakest; and if
the upheaving force is again exerted in the same direction, the crust of
the earth will give way anywhere rather than at the precise points where
the first rents were produced.
A large proportion of metalliferous veins have their opposite walls nearly
parallel, and sometimes over a wide extent of country. There is a fine
example of this in the celebrated vein of Andreasberg in the Hartz, which
has been worked for a depth of 500 yards perpendicularly, and 200
horizontally, retaining almost every where a width of 3 feet. But many
lodes in Cornwall and elsewhere are extremely variable in size, being 1 or
2 inches in one part, and then 8 or 10 feet in another, at the distance of
a few fathoms, and then again narrowing as before. Such alternate swelling
and contraction is so often characteristic as to require explanation. The
walls of fissures in general, observes Sir H. De la Beche, are rarely
perfect planes throughout their entire course, nor could we well expect
them to be so, since they commonly pass through rocks of unequal hardness
and different mineral composition. If, therefore, the opposite sides of
such irregular fissures slide upon each other, that is to say, if there be
a fault, as in the case of so many mineral veins, the parallelism of the
opposite walls is at once entirely destroyed, as will be readily seen by
studying the annexed diagrams.
[Illustration: Fig. 517. Schematic sketch.]
[Illustration: Fig. 518. Schematic sketch.]
[Illustration: Fig. 519. Schematic sketch.]
Let _a b_, fig. 517., be a line of fracture traversing a rock, and let _a
b_, fig. 518., represent the same line. Now, if we cut a piece of paper
representing this line, and then move the lower portion of this cut paper
sideways from _a_ to _a'_, taking care that the two pieces of paper still
touch each other at the points 1, 2, 3, 4, 5, we obtain an irregular
aperture at _c_, and isolated cavities at _d d d_, and when we compare such
figures with nature we find that, with certain modifications, they
represent the interior of faults and mineral veins. If, instead of sliding
the cut paper to the right hand, we move the lower part towards the left,
about the same distance that it was previously slid to the right, we obtain
considerable variation in the cavities so produced, two long irregular open
spaces, _f f_, fig. 519., being then formed. This will serve to show to
what slight circumstances considerable variations in the character of the
openings between unevenly fractured surfaces may be due, such surfaces
being moved upon each other, so as to have numerous points of contact.
[Illustration: Fig. 520. Schematic sketch.]
Most lodes are perpendicular to the horizon, or nearly so; but some of
them have a considerable inclination or "hade," as it is termed, the
angles of dip varying from 15 deg. to 45 deg.. The course of a vein is
frequently very straight; but if tortuous, it is found to be choked up
with clay, stones, and pebbles, at points where it departs most widely
from verticality. Hence at places, such as _a_, fig. 520., the miner
complains that the ores are "nipped," or greatly reduced in quantity,
the space for their free deposition having been interfered with in
consequence of the pre-occupancy of the lode by earthy materials. When
lodes are many fathoms wide, they are usually filled for the most part
with earthy matter, and fragments of rock, through which the ores are
much disseminated. The metallic substances frequently coat or encircle
detached pieces of rock, which our miners call "horses" or "riders."
That we should find some mineral veins which split into branches is also
natural, for we observe the same in regard to open fissures.
_Chemical deposits in veins._--If we now turn from the mechanical to the
chemical agencies which have been instrumental in the production of mineral
veins, it may be remarked that those parts of fissures which were not
choked up with the ruins of fractured rocks must always have been filled
with water; and almost every vein has probably been the channel by which
hot springs, so common in countries of volcanos and earthquakes, have made
their way to the surface. For we know that the rents in which ores abound
extend downwards to vast depths, where the temperature of the interior of
the earth is more elevated. We also know that mineral veins are most
metalliferous near the contact of plutonic and stratified formations,
especially where the former send veins into the latter, a circumstance
which indicates an original proximity of veins at their inferior extremity
to igneous and heated rocks. It is moreover acknowledged that even those
mineral and thermal springs which, in the present state of the globe, are
far from volcanos, are nevertheless observed to burst out along great lines
of upheaval and dislocation of rocks.[496-A] It is also ascertained that
all the substances with which hot springs are impregnated agree with those
discharged in a gaseous form from volcanos. Many of these bodies occur as
veinstones; such as silex, carbonate of lime, sulphur, fluor-spar, sulphate
of barytes, magnesia, oxide of iron, and others. I may add that, if veins
have been filled with gaseous emanations from masses of melted matter,
slowly cooling in the subterranean regions, the contraction of such masses
as they pass from a plastic to a solid state would, according to the
experiments of Deville on granite (a rock which may be taken as a
standard), produce a reduction in volume amounting to 10 per cent. The slow
crystallization, therefore, of such plutonic rocks supplies us with a force
not only capable of rending open the incumbent rocks by causing a failure
of support, but also of giving rise to faults whenever one portion of the
earth's crust subsides slowly while another contiguous to it happens to
rest on a different foundation, so as to remain unmoved.
Although we are led to infer, from the foregoing reasoning, that there has
often been an intimate connection between metalliferous veins and hot
springs holding mineral matter in solution, yet we must not on that account
expect that the contents of hot springs and mineral veins would be
identical. On the contrary, M. E. de Beaumont has judiciously observed that
we ought to find in veins those substances which, being least soluble, are
not discharged by hot springs,--or that class of simple and compound bodies
which the thermal waters ascending from below would first precipitate on
the walls of a fissure, as soon as their temperature began slightly to
diminish. The higher they mount towards the surface, the more will they
cool, till they acquire the average temperature of springs, being in that
case chiefly charged with the most soluble substances, such as the alkalis,
soda and potash. These are not met with in veins, although they enter so
largely into the composition of granitic rocks.[496-B]
To a certain extent, therefore, the arrangement and distribution of
metallic matter in veins may be referred to ordinary chemical action, or
to those variations in temperature, which waters holding the ores in
solution must undergo, as they rise upwards from great depths in the earth.
But there are other phenomena which do not admit of the same simple
explanation. Thus, for example, in Derbyshire, veins containing ores of
lead, zinc, and copper, but chiefly lead, traverse alternate beds of
limestone and greenstone. The ore is plentiful where the walls of the rent
consist of limestone, but is reduced to a mere string when they are formed
of greenstone, or "toadstone," as it is called provincially. Not that the
original fissure is narrower where the greenstone occurs, but because more
of the space is there filled with veinstones, and the waters at such points
have not parted so freely with their metallic contents.
"Lodes in Cornwall," says Mr. Robert W. Fox, "are very much influenced
in their metallic riches by the nature of the rock which they traverse,
and they often change in this respect very suddenly, in passing from one
rock to another. Thus many lodes which yield abundance of ore in
granite, are unproductive in clay-slate, or killas, and _vice versa_.
The same observation applies to killas and the granitic porphyry called
elvan. Sometimes, in the same continuous vein, the granite will contain
copper, and the killas tin, or _vice versa_."[497-A] Mr. Fox, after
ascertaining the existence at present of electric currents in some of
the metalliferous veins in Cornwall, has speculated on the probability
of the same cause having acted originally on the sulphurets and muriates
of copper, tin, iron, and zinc, dissolved in the hot water of fissures,
so as to determine the peculiar mode of their distribution. After
instituting experiments on this subject, he even endeavoured to account
for the prevalence of an east and west direction in the principal
Cornish lodes by their position at right angles to the earth's
magnetism; but Mr. Henwood and other experienced miners have pointed out
objections to the theory; and it must be owned that the direction of
veins in different mining districts varies so entirely that it seems to
depend on lines of fracture, rather than on the laws of voltaic
electricity. Nevertheless, as different kinds of rock would be often in
different electrical conditions, we may readily believe that electricity
must often govern the arrangement of metallic precipitates in a rent.
"I have observed," says Mr. R. Fox, "that when the chloride of tin in
solution is placed in the voltaic circuit, part of the tin is deposited in
a metallic state at the negative pole, and part at the positive one, in the
state of a peroxide, such as it occurs in our Cornish mines. This
experiment may serve to explain why tin is found contiguous to, and
intermixed with, copper ore, and likewise separated from it, in other parts
of the same lode."[497-B]
_Relative age of the different metals._--After duly reflecting on the facts
above described, we cannot doubt that mineral veins, like eruptions of
granite or trap, are referable to many distinct periods of the earth's
history, although it may be more difficult to determine the precise age of
veins; because they have often remained open for ages, and because, as we
have seen, the same fissure, after having been once filled, has frequently
been re-opened or enlarged. But besides this diversity of age, it has been
supposed by some geologists that certain metals have been produced
exclusively in earlier, others in more modern times,--that tin, for
example, is of higher antiquity than copper, copper than lead or silver,
and all of them more ancient than gold. I shall first point out that the
facts once relied upon in support of some of these views are contradicted
by later experience, and then consider how far any chronological order of
arrangement can be recognized in the position of the precious and other
metals in the earth's crust. In the first place, it is not true that veins
in which tin abounds are the oldest lodes worked in Great Britain. The
government survey of Ireland has demonstrated, that in Wexford veins of
copper and lead (the latter as usual being argentiferous) are much older
than the tin of Cornwall. In each of the two countries a very similar
series of geological changes has occurred at two distinct epochs,--in
Wexford, before the Devonian strata were deposited; in Cornwall, after the
carboniferous epoch. To begin with the Irish mining district: We have
granite in Wexford, traversed by granite veins, which veins also intrude
themselves into the Silurian strata, the same Silurian rocks as well as the
veins having been denuded before the Devonian beds were superimposed. Next
we find, in the same county, that elvans, or straight dikes of porphyritic
granite, have cut through the granite and the veins before mentioned, but
have not penetrated the Devonian rocks. Subsequently to these elvans, veins
of copper and lead were produced, being of a date certainly posterior to
the Silurian, and anterior to the Devonian; for they do not enter the
latter, and, what is still more decisive, streaks or layers of derivative
copper have been found near Wexford in the Devonian, not far from points
where mines of copper are worked in the Silurian strata.[498-A]
Although the precise age of such copper lodes cannot be defined, we may
safely affirm that they were either filled at the close of the Silurian or
commencement of the Devonian period. Besides copper, lead, and silver,
there is some gold in these ancient or primary metalliferous veins. A few
fragments also of tin found in Wicklow in the drift are supposed to have
been derived from veins of the same age.[498-B]
Next, if we turn to Cornwall, we find there also the monuments of a very
analogous sequence of events. First the granite was formed; then, about
the same period, veins of fine-grained granite, often tortuous (see fig.
496., p. 445.), penetrating both the outer crust of granite and the
adjoining fossiliferous or primary rocks, including the coal-measures;
thirdly, elvans, holding their course straight through granite, granitic
veins, and fossiliferous slates; fourthly, veins of tin also containing
copper, the first of those eight systems of fissures of different ages
already alluded to, p. 491. Here, then, the tin lodes are newer than the
elvans. It has indeed been stated by some Cornish miners that the elvans
are in some few instances posterior to the oldest tin-bearing lodes, but
the observations of Sir H. De la Beche during the survey led him to an
opposite conclusion, and he has shown how the cases referred to in
corroboration can be otherwise interpreted.[499-A] We may, therefore,
assert that the most ancient Cornish lodes are younger than the
coal-measures of that part of England, and it follows that they are of a
much later date than the Irish copper and lead of Wexford and some
adjoining counties. How much later it is not so easy to declare,
although probably they are not newer than the beginning of the Permian
period, as no tin lodes have been discovered in any red sandstone of the
Poikilitic group, which overlies the coal in the south-west of England.
There are lead veins in the Mendip hills which extend through the mountain
limestone into the Permian or Dolomitic conglomerate, and others in
Glamorganshire which enter the lias. Those worked near Frome, in
Somersetshire, have been traced into the Inferior Oolite. In Bohemia, the
rich veins of silver of Joachimsthal cut through basalt containing olivine,
which overlies tertiary lignite, in which are leaves of dicotyledonous
trees. This silver, therefore, is decidedly a tertiary formation. In regard
to the age of the gold of the Ural Mountains, in Russia, which, like that
of California, is obtained chiefly from auriferous alluvium, we can merely
affirm that it occurs in veins of quartz in the schistose and granitic
rocks of that chain. Sir R. Murchison observes, that no gold has yet been
found in the Permian conglomerates which lie at the base of the Ural
Mountains, although large quantities of iron and copper detritus are mixed
with the rolled pebbles of these same Permian strata. Hence it seems that
the Uralian quartz veins, containing gold and platinum, were not exposed to
aqueous denudation during the Permian era. But we cannot feel sure, from
any data yet before us, that such auriferous veins of quartz may not be as
old as the tin lodes of Cornwall, in which, as well as the more ancient
copper lodes of Ireland, some gold has been detected. We are also unable at
present to assign to the gold veins of Brazil, Peru, or California, their
respective geological dates. But, although enough is known to show that
Ovid's line about the "Age of Gold," "Aurea prima sata est aetas," would, by
no means, be an apt motto for a treatise on mining, it would be equally
rash in the present state of our inquiries to affirm, as some have done,
that gold was the last-formed of metals.
It has been remarked by M. de Beaumont, that lead and some other metals are
found in dikes of basalt and greenstone, as well as in mineral veins
connected with trap rocks, whereas tin is met with in granite and in veins
associated with the granitic series. If this rule hold true generally, the
geological position of tin in localities accessible to the miners will
belong, for the most part, to rocks older than those bearing lead. The tin
veins will be of higher relative antiquity for the same reason that the
"underlying" igneous formations or granites which are visible to man are
older, on the whole, than the overlying or trappean formations.
If different sets of fissures, originating simultaneously at different
levels in the earth's crust, and communicating, some of them, with
volcanic, others with heated plutonic masses, be filled with different
metals, it will follow that those formed farthest from the surface will
usually require the longest time before they can be exposed superficially.
In order to bring them into view, or within reach of the miner, a greater
amount of upheaval and denudation must take place in proportion as they
have lain deeper when first formed. A considerable series of geological
revolutions must intervene before any part of the fissure, which has been
for ages in the proximity of the plutonic rocks, so as to receive the gases
discharged from it when it was cooling, can emerge into the atmosphere. But
I need not enlarge on this subject, as the reader will remember what was
said in the 30th, 34th, and 37th chapters, on the chronology of the
volcanic and hypogene formations.
* * * * *
_Concluding Remarks._--The theory of the origin of the hypogene rocks, at a
variety of successive periods, as expounded in two of the chapters just
cited, and still more the doctrine that such rocks may be now in the daily
course of formation, has made and still makes its way, but slowly, into
favour. The disinclination to embrace it has arisen partly from an inherent
obscurity in the very nature of the evidence of plutonic action when
developed on a great scale, at particular periods. It has also sprung, in
some degree, from extrinsic considerations; many geologists having been
unwilling to believe the doctrine of the transmutation of fossiliferous
into crystalline rocks, because they were desirous of finding proofs of a
beginning, and of tracing back the history of our terraqueous system to
times anterior to the creation of organic beings. But if these expectations
have been disappointed, if we have found it impossible to assign a limit to
that time throughout which it has pleased an Omnipotent and Eternal Being
to manifest his creative power, we have at least succeeded beyond all hope
in carrying back our researches to times antecedent to the existence of
man. We can prove that man had a beginning, and that, all the species now
contemporary with man, and many others which preceded, had also a
beginning, and that, consequently, the present state of the organic world
has not gone on from all eternity, as some philosophers have maintained.
It can be shown that the earth's surface has been remodelled again and
again; mountain chains have been raised or sunk; valleys formed, filled
up, and then re-excavated; sea and land have changed places; yet
throughout all these revolutions, and the consequent alterations of
local and general climate, animal and vegetable life has been sustained.
This has been accomplished without violation of the laws now governing
the organic creation, by which limits are assigned to the variability of
species. The succession of living beings appears to have been continued
not by the transmutation of species, but by the introduction into the
earth from time to time of new plants and animals, and each assemblage
of new species must have been admirably fitted for the new states of the
globe as they arose, or they would not have increased and multiplied and
endured for indefinite periods.[501-A]
Astronomy had been unable to establish the plurality of habitable worlds
throughout space, however favourite a subject of conjecture and
speculation; but geology, although it cannot prove that other planets
are peopled with appropriate races of living beings, has demonstrated
the truth of conclusions scarcely less wonderful,--the existence on our
own planet of so many habitable surfaces, or worlds as they have been
called, each distinct in time, and peopled with its peculiar races of
aquatic and terrestrial beings.
The proofs now accumulated of the close analogy between extinct and recent
species are such as to leave no doubt on the mind that the same harmony of
parts and beauty of contrivance which we admire in the living creation, has
equally characterized the organic world at remote periods. Thus as we
increase our knowledge of the inexhaustible variety displayed in living
nature, and admire the infinite wisdom and power which it displays, our
admiration is multiplied by the reflection, that it is only the last of a
great series of pre-existing creations, of which we cannot estimate the
number or limit in times past.[501-B]
FOOTNOTES:
[489-A] Principles, &c. chap. iv. 8th ed. p. 49.
[491-A] Geol. Trans. vol. iv. p. 139.; Trans. Roy. Geol. Society
Cornwall, vol. ii. p. 90.
[492-A] Carne, Trans. of Geol. Soc. Cornwall, vol. iii. p. 238.
[492-B] Fournet, Etudes sur les Depots Metalliferes.
[493-A] Geol. Rep. on Cornwall, p. 340.
[493-B] Principles, ch. xxvii. 8th ed. p. 422.
[496-A] See Dr. Daubeny's Volcanos.
[496-B] Bulletin, iv. p. 1278.
[497-A] R. W. Fox on Mineral Veins, p. 10.
[497-B] Ibid. p. 38.
[498-A] I am indebted to Sir H. De la Beche for this information. See also
maps and sections of Irish Survey.
[498-B] Sir H. De la Beche, MS. notes on Irish Survey.
[499-A] Report on Geology of Cornwall, p. 310.
[501-A] See Principles of Geol., Book 3.
[501-B] See the author's Anniv. Address to the Geol. Soc. 1837. Proceedings
of G. S. No. 49. p. 520.
INDEX.
A.
AEgean Sea, mud of, 35.
animal life in depths of, 137.
Agassiz, M., cited, 192. 276. 300. 335. 344. 345.
on parallel roads, 87.
on fossil fishes of molasse and faluns, 171.
on fossil fish of Lias, 275.
on fossil fish in Permian marl-slate, 304.
on fish from Sheppey, 202.
on foot-prints, 299.
on fishes of brown coal, 417.
on glaciers, 140. 143.
Age of formation determined by fragments of older rock, 101.
of metamorphic rocks, 482.
test of, in plutonic rocks by relative position, 449.
of Spanish volcanos, 414.
of volcanic rocks, how tested, 397-400.
Aix-la-Chapelle, hot spring at, 477.
Alabaster defined, 13.
Alabama, cretaceous shingle of, 225.
Alberti on the Keuper, 287.
Alexander, Capt., marine shells in crag, found by, 149.
Alluvium, term explained, 79.
in Auvergne, 80.
of the Wealden, 252.
Alps, nummulitic formation of, 205.
curved strata of, 58.
Swiss and Savoy, cleavage of, 470.
of Switzerland, 483.
Alpine blocks on the Jura, 142.
erratics, 140.
Altered rocks, 381. 456.
by subterranean gases, 476.
Alternations of rocks, 14.
of marine and freshwater formations, 32.
Alumine in rocks, 11.
_Amblyrhynchus cristatus_, 279.
America, North, lithodomi in beaches of, 78.
South, cretaceous strata, 225.
South, gradual rise of parts of, 46.
South, fossils of, 157.
Amygdaloid, 372.
Amphitherium, 268.
Andelys, chalk cliffs at, 239.
Andernach, strata near, 417.
Andes, plutonic rocks of, 453.
rocks drifted from to Chiloe, 144.
Anthracite in Rhode Island, 478.
Anticlinal line, 48. 57.
Antrim, rocks altered by dikes in, 382.
Antwerp, strata like Suffolk crag near, 166.
_Apateon pedestris_, a carboniferous reptile, 336.
Apennines, limestone in, 482.
Appalachian coal-field, 329.
Appalachians, altered rocks in, 478.
_Apteryx_ in New Zealand, 158.
Aqueous rocks defined, 2.
rocks, mineral character of, 97.
deposits, superposition of, 96.
Arbroath, section from, to the Grampians, 48.
Archegosaurus, figure of, 337.
Archiac, M., cited, 143.
on fossils in chalk, 221.
on shells in French Lower Eocene, 196.
Ardeche, lava in, 385.
Arenaceous rocks described, 11.
Argillaceous rocks, 11.
schist, 465.
Argile plastique, or Lower Eocene, 196.
Argyleshire, trap-vein in cliff, 379.
Arran, age of granite in, 459.
section of, 461.
dike of greenstone in, 379.
Arthur's Seat, altered strata of, 383.
Ashby-de-la-Zouch, fault in coal-field of, 69.
Ascension, lamination of volcanic rocks in, 480.
Asterophyllites, 314.
Asti, formations at, 167.
Atherfield, cretaceous strata of, 219.
Augite, 369.
Aurillac, freshwater strata of, 188.
Austen, Mr., R. A. C., on phosphate of lime, 219.
Australian cave-breccias, 155.
Auvergne freshwater formations, 186.
succession of changes in, 180.
lacustrine strata, 181.
mineral veins of, 493.
indusial limestone, 184.
extinct volcanos of, 422.
alluvium in, 80.
Aymestry limestone, 352.
B.
Bagshot sands, 199.
Bacillaria, fossil in tripoli, 25.
Baiae, Bay of, strata in, 403.
Bakewell, Mr., on cleavages of Alps, 470.
Balgray, near Glasgow, stumps of trees in coal, 317.
Bahia Blanca, fossil remains at, 148.
Baltic, brackish water strata on coast of, 114.
Barcombe, chalk flints near, 253.
Barton Cliff, 198.
Barrande, M., on trilobites, 358.
Basterot, M. de, on tertiaries of south of France, 105.
Basalt, 371.
columnar in the Eifel, 387.
columnar, near Vicenza, 386.
columnar, structure of, 384.
Basset, term explained, 56.
Batrachian, eggs of, in Old Red, Scotland, Postscript, x.
Bayfield, Capt., on fossil shells in Canada, 134.
on inland cliffs in Gulf of St. Lawrence, 78.
Bean, Mr., shells similar to those in Norwich crag found in Yorkshire
by, 149.
Bean, Mr., on fossil shells from oolite, 272.
Beachy Head, chalk cliffs near, 246.
Beaumont, M. E. de, on rocks of Hautes Alpes, 455.
on lamination of volcanic rocks, 480.
Beaumont, M. E. de, on Swiss Alps, 484.
on quartz, 439.
on oolite formation in France, 221.
Beck, Dr., on kelp, 217.
on graptolites, 357.
cited, 162. 186.
Belemnite in Oxford clay, 262.
Berger, Dr., on rocks altered by dikes, 382.
Bergmann on trap, 366.
Berlin, tertiary strata near, 177.
Bermuda Islands, lagoons in, 216.
rocks of, 78.
Bernese Alps, gneiss in, 484.
Berthier, on augite and hornblende, 369.
Beudant, M., on Hungary, 421.
Beyrich, Prof., on tertiary strata near Berlin, 177.
Biaritz, calcareous cliffs of, 72.
Bilin, tripoli, composed of infusoria, 25.
Binney, Mr., on stigmaria and sigillaria, 315.
Birds, footprints of, 298.
fossil, scarcity of, Postscript, xix.
Bischoff, Prof., experiments on heat, 476.
on steam at a high temperature, 477.
Blainville, on number of genera of mollusca, 28.
Boase, Dr., cited, 479.
Boblaye, M., on inland cliffs, 73.
cited, 431.
Bog-iron ore, 26.
Borrowdale, black-lead of, 38.
Bordeaux, tertiary deposits of, 171.
Bosquet, M., on Maestricht beds, 210.
Bothnia, Gulf of, land upheaved, 45.
Boue, M., on arrangement of rocks, 95.
on fossil shells in Hungary, 421.
on Carrara marble, 482.
on Swiss Alps, 484.
Bonelli, on strata in Italy, 106.
Boulder formation in Canada, 133.
period, fauna of, 126.
formation, mineral ingredients of, 126.
formation in England, 130.
Boulders, 123.
striated, 136.
Boutigny, M., cited, 441.
Bowen, Lieut. A., R.N., drawings of rocks in Gulf of St. Lawrence, 78.
Bowerbank, Mr., on fossil flora of Sheppey, 200.
Bowman, Mr., on coal-seams, 330.
Bracklesham Bay, characteristic shells of, 199.
Brash, term, explained, 81.
Bravard, M., on Auvergne mammalia, 188. 425.
Breccia on ancient coast lines, 73.
Brickenden, Captain, on Elgin fossils, Postscript, ix.
Brighton, elephant bed of, 256.
Bristol, dolomitic conglomerate near, 305.
section of strata near, 102.
Brocchi, on Subapennines, 105. 167.
Brockedon, Mr., on black-lead, 38.
Broderip, Mr., cited, 270.
Brodie, Rev. P.B., on fossil insects, 281.
cited, 207.
Bromley, oyster-bed near, 204.
Brongniart, M. Adolphe, on Eocene flora, 200.
on flora of cretaceous period, 223.
on fossil plants in lias, 282.
on plants of Bunter sandstein, 288.
on fossil fir-cones, 313.
on Permian flora, 307.
on sigillaria, 314.
on asterophyllites, 314.
on stigmaria, 315.
age of acrogens, 316.
on endogens, 316.
Brongniart, M. Alex., on Paris tertiaries, 104.
on Eocene formation, 175.
on shells of nummulitic formation, 205.
on coal mine near Lyons, 319.
Brora, coal formation, 272.
Brora, granite near, 458.
Brown, Mr. Richard, on stigmariae, 315.
on coal formation, 415.
on Cape Breton coal-field, 324. 334.
on carboniferous rain-prints, Postscript, xii.
Buckland, Dr., on cave at Kirkdale, 154.
on coal plants, 317.
on coprolites in chalk, 216.
on fish of Lias, 276.
on footprints, 291.
on mountains of Caernarvonshire, 130.
on oyster bed near Bromley, 204.
on parallel roads, 87.
on term Poikilitic, 286.
on saurians of Lias, 278.
on sudden destruction of saurians, 280.
cited, 155. 231. 233. 267. 268.
Buddle, Mr., on creeps in coal mines, 50.
on ancient river-channels of coal period, 334.
Buist, Dr. G., on saltness of Red Sea, 296.
Bunbury, Mr. C. J. F., on plants of coal-field, 285.
Bunter sandstein, 288.
Burmeister on trilobites, 358.
Burnes, Sir A., cited, 295.
C.
Caernarvonshire, ancient glaciers of, 130.
Calamites, figures of, 313.
near Pictou, 319.
Calcaire grossier, 193.
siliceux, 195.
Calcareous rocks, 12.
rocks of Gulf of Spezia, 482.
cliffs of Biaritz, 72.
Caldcleugh, Mr., cited, 399.
Caldera of Palma, 392.
Cambrian group, 361.
volcanic rocks, 435.
Campagna di Roma, tuffs of, 408.
Canada, shells in drift of, 134.
Cantal, freshwater formation of, 188.
igneous rocks of, 429.
freshwater beds of, 429.
Cape Breton, coal measures of, 324.
Wrath, granite veins in, 444.
Caradoc sandstone, 356.
Carbonaceous shale, 271.
Carbonate of lime scarce in metamorphic rocks, 487.
Carbonate of lime in rocks, how tested, 12.
Carboniferous group, 308.
flora, 310.
period, plutonic rocks of, 456.
period, volcanic rocks of, 432.
reptiles, 335.
Carne, Mr., on Cornish lodes, 491. 492.
Carrara marble, 482.
_Caryophyllia caespitosa_, bed of, in Sicily, 151.
Castrogiovanni, bent strata near, 58.
Catalonia, volcanic region of, 408.
Cautley, Captain, on Sewalik hills, 173.
Caves in Europe, 155.
at Kirkdale, 154.
in Sicily, 153.
in Australia, 156.
Central France, Upper Eocene of, 178.
Cetacea, fossil, rarity of, Postscript, xxi.
Chalk, pinnacle of, near Sherringham, 129.
of Faxoe, 210. and Postscript, xv.
white, fossils of, 26.
white, section of, 211.
white, extent and origin of, 215.
white, animal origin of, 216.
pebbles in, 217.
difference of, in north and south of Europe, 221.
Chalk cliffs, inland, on Seine, 238.
needles of, in Normandy, 241.
flints, bed of, near Barcombe, 253.
Chambers, Mr., cited, 88.
Chamisso, cited, 217.
Chara, in freshwater strata, 31.
in flints of Cantal, 189.
in Eocene strata of France, 176.
in Purbeck beds, 232.
Charlesworth, Mr. E., cited, on Crag, 162.
Charpentier, M., on Alpine glaciers, 140.
on Swiss glaciers, 143.
Cheirotherium, footprints of, 290. 337.
Chemical and mechanical deposits, 33.
Chili, earthquake in, 61.
gold mines in, 472.
Chiloe, rocks drifted from Andes to, 144.
Chlorite schist, 465.
Christiania, dike near, 380.
trap rocks, passage of granite into, at, 441.
granite near, 457.
gneiss near, 446.
intrusion of granite into beds near, 446.
Chronological groups, 101.
Cinder-bed, Purbeck, 231.
Claiborne, marine shells of, 206.
Clausen, Mr., cited, 158.
Clay, defined, 11.
Clay-slate, 465. 468.
Clay-ironstone, 326.
Clays, plastic, 203.
Cleavage of rocks, 468.
Climate of drift period, 139.
of coal period, 335.
Coal, zigzag flexures of, near Mons
group, 308.
measures, 308. 309.
how formed, 317.
pipes, danger of, 318.
mine, near Lyons, 319.
seam at Brownsville, Pennsylvania, view of, 332.
conversion of into lignite, 333.
formation at Brora, 272.
seams, continuity of, 334.
period, climate of, 335.
strata, footprints of reptiles in, 337.
Coal-field at Burdiehouse, 325.
of Ashby-de-la-Zouch, 69.
United States, diagram of, 327.
of Yorkshire, fossils of, 325.
Coalbrook Dale, beetles in coal of, 335.
fossil cones in, 313.
coal measures of, 324.
faults in, 62.
Cockfield Fell, rocks altered by dikes, 383.
Columbia, vinegar river of, 191.
Colchester, Mr., on mammalian remains at Kyson, 203.
Come, ravine in lava of, 427.
Cones in Val di Noto, 389.
and craters, absence of, in England, 6.
and craters, 367.
Conifers, fossil trees, 316.
Concretionary structure, 37.
Conglomerate, or pudding-stone, 11.
dolomitic, 305.
vertical in Scotland, &c., 47.
Connecticut, valley of the, 297.
beds, antiquity of, 300.
Conrad, Mr., on cretaceous rocks, 224.
Conybeare, Mr., cited, 64. 69. 244. 274.
on Plesiosaurus, 278.
on oolite and lias, 283.
on term Poikilitic, 286.
on crocodiles, 201.
Cook, Capt., on _Fucus giganteus_, 217.
Coprolites in chalk, 216.
Coralline crag, fossils in, 164.
Coral islands and reefs, 34. 46.
rag of Oolite, 260.
Corals, figures of, in crag, 165.
of Devonian system, 346.
of Devonian strata in United States, 349.
in Wenlock formation, 355.
Corinth, corrosion of rocks by gases near, 477.
Cornbrash, 263.
Cornwall, granite veins in, 445. 474.
mineral veins in, 490. 494.
tin of, newer than Irish copper, 499.
Cotta, Dr. B., on granite in Saxony, 459.
Crag coralline, fossils in, 164.
comparison of faluns and, 170.
of Suffolk, red and coralline, 105. 162.
fluvio-marine, Norwich, 148.
Craigleith fossil trees, 40.
quarry, slanting tree in, 320.
Crater of Island of St. Paul, 395.
Craven fault, 64.
Creeps in coal-mines described, 52.
Credneria in Quadersandstein, Postscript, xvi.
Cretaceous rocks of Pyrenees, 455.
group, 209. 219. and Postscript, xvi.
strata in South America and India, 225.
period, plutonic rocks of, 455.
volcanic rocks, 431.
rocks in United States, 224.
Crocodiles near Cuba, 279.
Croizet, M., on Auvergne fossil mammalia, 188.
Cromer, contorted drift near, 129.
"Crop out," term explained, 55.
Crust of earth defined, 2.
Crystalline limestone, 302.
rocks, erroneously termed primitive, 9.
schists defined, 7.
Curved strata, 47.
strata, experiments to illustrate, 49.
Cutch, Runn of, 295.
Cuvier, M., on Eocene formation, 175.
on Amphitherium, 268.
cited, 192.
on tertiary strata near Paris, 104.
on fossils of Montmartre, 191.
Cyclopian Islands, 401.
Cypris in Lias, 281.
in Wealden, 228.
in marl of Auvergne, 183.
Cystideae in Silurian rocks, 358.
D.
Dana, Mr., on coprolites of birds, 299.
on coral reef in Sandwich Islands, 216.
on volcanos of Sandwich Islands, 394. 406. 423.
Dartmoor, granite of, 456.
Darwin, Mr., cited, 217.
on boulders and glaciers in South America, 144.
on cleavage in South America, 471.
on coral islands of Pacific, 216.
on dike in St. Helena, 406.
on habits of ostrich, 299. and Postscript, xx.
on fossils in South America, 148.
on _Fucus giganteus_, 217.
on gradual rise of part of S. America, 46.
on lamination of volcanic rocks, 480.
on parallel roads, 87.
on plutonic rocks of Andes, 453.
on recent strata near Lima, 115.
on saurians in Galapagos Islands, 279.
on sinking of coral reefs, 46.
on Welsh glaciers, 131.
Daubeny, Dr., on the Solfatara, 477.
Daubeny, Dr., on volcanos in Auvergne, 428.
Dax, inland cliff at, 72.
Deane, Dr., on footprints, 298.
Dean, forest of, coal in, 334.
Dechen, Prof. von, on reptiles in Saarbrueck coal-field, 336.
De Koninck, cited, 176. 178.
De la Beche, Sir H., cited, 231. 233. 281.
on Carrara marble, 482.
on clay beds, 283.
on clay-ironstone, 326.
on coal-measures near Swansea, 309.
on fossil trees, S. Wales, 318.
on granite of Dartmoor, 474.
on mineral veins, 493. 495. 498.
on term supracretaceous, 103.
on trap of New Red Sandstone period, 432.
Deluge, 4.
Denudation explained, 66.
of the Weald Valley, 242.
terraces of, in Sicily, 75.
Derbyshire, lead veins of, 497.
Deshayes, M., identification of shells, 176.
on fossil shells in Hungary, 421.
on Lower Eocene shells, 196.
on tertiary classification, 110.
Desmarest, cited, 183.
on trappean rocks, 91.
Desnoyers, M., on Faluns of Touraine, 106.
Desor, M., on glacial fauna in N. America, 133.
Devonian flora, 349.
strata in United States, 349.
system, term explained, 346.
Diagonal, or cross stratification, 16.
Dicotyledonous leaves in chalk, Postscript, xvi.
Dike in St. Helena, 406.
Dikes at Palagonia in Sicily, 407.
trappean, crystalline in centre, 380.
defined, 6.
in Scotland, 378.
of Somma, 404.
Diluvium, popular explanation of term, 132.
Dip, term explained, 53.
Dolerite, or greenstone, 372.
Dolomite defined, 13.
Dolomitic conglomerate, 305.
Doue, M. B. de, on volcanos of Velay, 428.
Drift contorted, near Cromer, 129.
in Ireland, 131.
in Norfolk, 126.
meteorites in, 145.
northern, in Scotland, 125.
northern, in North Wales, 130.
of Scandinavia, North Germany, and Russia, 121.
period, climate of, 139.
period, subsidence in, 135.
shells in Canada, 134.
Dudley limestone, 354.
shales of coal near, 474.
Dufrenoy, M., on granite of Pyrenees, 475.
Duff, Mr. P., on reptile of Old Red, Postscript, ix.
on hill of Gergovia, 430.
Dunker, Dr., on Wealden of Hanover, 237.
E.
Echinoderms of coralline crag, 166.
Echinus, figure of, 23.
Egerton, Mr., on fossils of Southern India, 225.
Egerton, Sir P., on fish of marl slate, 304.
on fossil fish of Connecticut beds, 300.
on fossils of Isle of Wight, 198.
on saurians and fish in New Red Sandstone, 289.
on Ichthyosaurus, 276.
Eggs, fossil, of snake, 120.
Ehrenberg, Prof., on bog-iron ore, 26.
on infusoria, 24.
Elephant bed, Brighton, 256.
_Elephas primigenius_, jaw figured, 159.
Elvans of Ireland and Cornwall, 498.
term explained, 457.
Encrinites, figure of, 264.
Endogens, 316.
Eocene, foraminifera, 194.
formations, 174.
formations in England, 197.
granite, 451.
lower, in France, 176-191.
middle, in France, 191.
strata, in United States, 206.
upper, near Louvain, 177.
term defined, 111.
upper, of Central France, 178.
volcanic rocks, 429.
Equisetaceae, 313.
Equisetum of Virginian oolite, 284.
_Equisetum_ giganteum, 314.
Erman on meteoric iron in Russia, 145.
Erratics, Alpine, 140.
northern origin of, 123.
Escher, M., on boulders of Jura, 143.
Etna, deposits of, 401.
Eurite, 440.
Euritic porphyry described, 447.
Exogens, 316.
F.
Faluns of Touraine, 106. 168.
Faluns, comparison of, and crag, 170.
Falconer, Dr., on Sewalik Hills, 173.
Falkland Islands, 88.
Farnham, phosphate of lime near, 219.
Fault, term explained, 62.
Faults, origin of, 64.
Faxoe, chalk of, 210. and Postscript, xv.
Felixstow, remains of cetacea found near, 166.
Felspar, 369.
Ferns in coal-measures, 310.
Fife, altered rock in, 383.
Fifeshire, trap dike in, 434.
Megalichthys found in Cannel coal in, 336.
Fishes, fossil, of Upper Cretaceous, 214.
of Old Red Sandstone, 343.
of Wealden, 229.
fossil, of brown coal, 416.
Fissures filled with metallic matter, 490.
_See_ mineral veins.
Fitton, Dr., on division of lower cretaceous formation, 219.
cited, 227. 231. 233. 237. 244. 247.
Fleming, Dr., on scales of fish in Old Red, 343.
on trap-rocks in coal-field of Forth, 432.
on trap dike in Fifeshire, 434.
Flora, carboniferous, 310.
cretaceous, 223.
Devonian, 349.
of London Clay, 200.
permian, 305. 307.
Floetz, term explained, 91.
Flysch, explanation of term, 206.
Footprints of birds, 297. and Postscript, xx.
of reptilians, 337.
fossil, 289. 290. 291. 297.
Foraminifera in chalk, 26.
Eocene, 194.
Forbes, Prof. E., on Caradoc sandstone, 359.
on Cystideae, 358.
on shells in crag deposits, 162.
on cretaceous fossil shells, 224.
on fossils of the faluns, 169.
on fossils in drift in South Ireland, 131.
on deep-sea origin of Silurian strata, 360.
on echinoderms of coralline crag, 166.
on fauna of boulder period, 125.
on migrations of mollusca in glacial period, 166.
on fossils of Purbeck group, 231. 233.
on strata at Atherfield, 219.
on changes of Wealden testacea, 235.
on volcanic rocks of Oolite period, 432.
on depth of animal life in AEgean, 35. 137.
cited, 225.
Forbes, Prof. James, on zones in volcanic rocks, 480.
on the Alps, 143.
Forchhammer, on scratched limestone, 122.
Forest, fossil, in Norfolk, 127. 130.
Forfarshire, Old Red Sandstone in, 479.
Formation, term defined, 3.
Fossil, term defined, 4.
Fossils of chalk and greensand, figures of, 212.
in chalk at Faxoe, 210.
of coralline crag, 164.
of Devonian system, 346. and Postscript, x. xi.
of Eocene strata in United States, 207.
in faluns of Touraine, 169.
freshwater and marine, 27.
of Isle of Wight, 198.
of Lias, 274.
of Ludlow formation, 352.
of mountain limestone, 340.
of London Clay, 200.
of Maestricht beds, 209.
of Lower Greensand, 220.
of New Red Sandstone, 287. and Postscript, xiii.
of Oolite, 259. 266.
of Red Crag, 164.
of Silurian rocks, 353. and Postscript, vii.
of Solenhofen, 260.
of Upper Greensand, 218.
of Wealden, 236.
test of the age of formations, 98.
Fossil fish of Permian limestone, 303.
of Connecticut beds, 300.
of Richmond, U. S., strata, 285.
of Old Red Sandstone, 343.
scales of Permian, figured, 305.
footsteps, 289. 290. 291.
ferns in carbonaceous shale, 271.
forest in Nova Scotia, 321.
forest near Wolverhampton, 319.
forest in Isle of Portland, 233.
plants in Wealden, 230.
plants of Lias, 282.
plants of Bunter sandstein, 288.
trees erect, 317.
wood, petrifaction of, 39.
wood perforated by Teredina, 24.
remains in caves, 154.
shells from Etna, 401.
shells near Grignon, 193.
shells of Mayence strata, 178.
shells in Virginia, 172.
Fossiliferous strata, tabular view of, 361.
Fournet, M., on mineral veins of Auvergne, 493.
on disintegration of rocks, 476.
on quartz, 439.
Fox, Mr. R. W., 472.
on Cornish lodes, 497.
Fox, Rev. Mr., on extinct quadrupeds of Isle of Wight, 198.
Freshwater beds of Isle of Wight, 197.
deposits in valley of Thames, 146.
land shells numerous in, 27.
Freshwater formations of Auvergne, 186.
Freshwater formation, how distinguished from marine, 27. 28. 30.
remains of fish in, 32.
associated with Norfolk drift, 127.
Chara in, 31.
Cypris in, 31.
Freshwater shells in brown coal near Bonn, 417.
_Fucus giganteus_, 217.
_vesiculosus_, growth of, in Jutland, 217.
_vesiculosus_ in Lym-Fiord, 33.
Fundy, Bay of, impressions in red mud of, 297.
G.
Gaillonella fossil in Tripoli, 25.
ferruginea in bog-iron ore, 26.
Galapagos Islands, animals of, 279.
Garnets in altered rock, 382.
Gases, subterranean rocks altered by, 476.
Gault, 218.
Gavarnie, flexures of strata, 59.
Geology defined, 1.
Gergovia, hill of, 430.
Giant's Causeway, columns at, 384.
Gibbes, R. W., cited, 207.
Glacial phenomena, northern, origin of, 132.
Glaciers, Alpine, 140.
Glaciers on Caernarvonshire mountains, 130.
Glasgow, marine strata near, 148.
Glen Roy, parallel roads of, 86.
Glen Tilt, granite of, 442.
Gneiss, altered by granite, 445.
in Bernese Alps, 484.
at Cape Wrath, 444.
near Christiania, 446.
described, 464.
Gold, age of, in Ireland, 498.
age of, in Ural Mountains, 499.
Goldfuss, Prof., on reptiles in coal-field, 336.
Goeppert, Prof., on beds of coal, 316.
on petrifaction, 40.
Graham's Island, 389. 407.
Grampians, old red conglomerates in, 47.
Granite described, 7. 436. 438. 444.
passage of into trap, 441.
porphyritic, 439.
and limestone, junction of in Glen Tilt, 442.
syenitic, 440.
talcose, 440.
schorly, 440.
of Cornwall and Dartmoor, 474.
of Swiss Alps, 484.
rocks in connection with mineral veins, 500.
of Saxony, 459.
Granites, oldest, 458.
varieties of, 444.
veins in Cornwall, 445.
veins in Cape Wrath, 444.
veins in Table Mountain, 443.
vein in White Mountains, 450.
of Arran, age of, 459.
near Christiania, 457.
dikes in Mount Battock, 443.
Graphite, powder of, consolidated by pressure, 38.
Graptolites, 357.
Grateloup, M., on fossils in chalk, 223.
Grauwacke, term explained, 350.
Greenland, sinking of coast, 46.
Greensand, upper, 218.
fossils of, 212.
Greensburg, Pennsylvania, footprints of reptile in coal strata at, 337.
Greenstone or Dolerite, 372.
dike of, in Arran, 379.
Gres de Beauchamp, Paris Basin, 193.
Grignon, fossil shells near, 193.
Grit defined, 11.
Guadaloupe, human skeleton of, 115.
Guidoni on Carrara marble, 482.
Gutbier, Col. von, on Permian flora, 305. 307.
Gryphaea, fossil figure of, 22.
Gypseous marls, 186.
series, 191.
Gypsum defined, 13.
H.
Hall, Sir Jas., experiments on fused minerals, 406.
on curved strata, 48.
Capt. B., cited, 378. 401. 443.
Hamilton, Sir W., on eruption of Vesuvius, 405.
Harris, Major, on salt lake in Ethiopia, 296.
Hartz, Bunter sandstein of, 288.
Hastings, Lady, fossils collected by, 198.
Hastings sand, 229.
bed, shells of, 229.
Hautes Alpes, rocks of, 455.
Hauey cited, 369.
Hawkshaw, Mr., on fossil trees in coal, 317.
Hayes, T. L., on icebergs, 123.
Hebert, M., cited on Upper Eocene beds, 176.
Hebrides, dikes of trap in, 379.
Heidelberg, varieties of granite near, 444.
Henfrey, Mr. A., on food of Mastodon, 138.
Henslow, Prof., on fossil cetacea in Suffolk, 166.
on fossil forests, 233.
on dike and altered rock near Plas Newydd, 381.
Henry, Mr., cited, 476.
Herschel, Sir J., on slaty cleavage, 472.
Hertfordshire pudding-stone, 35.
Hibbert, Dr., on volcanic rocks, 428.
on coal field at Burdiehouse, 325.
cited, 419.
High Teesdale, garnets in altered rock at, 382.
Hildburghausen, footprints of reptile at, 289. 290.
Hippurite limestone, 221.
Hitchcock, Prof., on footprints, 297.
Hoffmann, Mr., on Lipari Islands, cited, 476.
on cave near Palermo, 74.
on Carrara marble, 482.
Hooghly river, analysis of water, 41.
Hopkins, Mr., on fractures in Weald, 251.
Horizontality of strata, 15.
of roads of Lochaber, 88.
Hornblende, 369.
schist, 464. 478.
Horner, Mr., on geology of Eifel, 415.
on Megalichthys, 336.
Hubbard, Prof., on granite vein in White Mountains, 450.
Hugi, M., on Swiss Alps, 484.
Humboldt, cited, 314.
on uniform character of rocks, 486.
Hungary, trachyte of, 442.
volcanic rocks of, 421.
Hunt, Mr., experiments on clay-ironstone, 326.
Hutton, opinions of, 60.
Huttonian theory, 92.
Hypogene, term defined, 9.
rocks, mineral character of, 485.
or metamorphic limestone, 465.
I.
Ibbetson, Capt., on chalk Isle of Wight, 215.
Ice, rocks drifted by, 122.
Icebergs, stranding of, 129. 137.
Iceland, icebergs drifted to, 137.
Ichthyolites of Old Red Sandstone, 349.
_Ichthyosaurus communis_, figure of, 277.
Igneous rocks, 6.
of Siebengebirge and Westerwald, 417.
rocks of Val di Noto, 389.
_Iguanodon Mantelli_, 227. 229.
India, cretaceous system in, 225.
freshwater deposits of, 173.
oolitic formation in, 285.
Indusial limestone, Auvergne, 184.
Infusoria in tripoli, 24.
Inland sea-cliffs in South of England, 71.
Insects in Lias, 281.
Ireland, drift in, 131.
Ischia, volcanic cones in, 403.
Post-Pliocene strata of, 113.
Isle of Wight, freshwater beds of, 197.
Isomorphism, theory of, 370.
J.
Jackson, Dr. C. T., analysis of fossil bones, 138.
James, Capt., on fossils in drift South Ireland, 131.
Java, stream of sulphureous water, 191.
Jobert, M., on hill of Gergovia, 430.
Joints, 469.
Jorullo, lava stream of, 450.
Jura, alpine blocks on, 142.
limestone, 261.
structure of, 55.
K.
Kangaroo, fossil and recent, jaws figured, 156.
Kaup, Prof., on footprints of Cheirotherium, 290.
Kaye, Mr., on fossils of Southern India, 225.
Keeling Island, fragment of greenstone in, 217.
Keilhau, Prof., cited, 457. 474.
on dike of greenstone, 380.
on gneiss near Christiania, 446.
on granite, 447.
Kelloway rock, 34.
Kentish chalk, sand-galls in, 82.
Keuper, the, 287.
Killas in granite of Cornwall, 474.
Kimmeridge clay, 260. and Postscript, xxi.
King, Dr., on footprints of reptile, 337.
King, Mr., on Permian group and fossils, 301. 302.
Kirkdale, cave at, 154.
Kotzebue cited, 217.
Kyson, in Suffolk, strata of, 202.
L.
Labyrinthodon, 292. 288. 289.
Lacustrine strata of Auvergne, 181.
Lagoons at mouth of rivers, 33.
of Bermuda Islands, 216.
Lake craters of Eifel, 419.
crater of Laach, 420.
Lamarck on bivalve mollusca, 29.
Land, rising and sinking, 45.
Laterite, 376.
Lava, 373.
current, Auvergne, 425.
relation to trap, 387.
stream of Jorullo, 450.
of Stromboli, 450.
Lea, Mr., footprints of reptile discovered by, 340.
Lead, veins of, in Permian rocks, 499.
Lehman on classification of rocks, 90.
Leibnitz, theory of, 94.
Lepidodendra, 312.
Lewes, coomb near, 250.
Lias, 273.
period, Volcanic rocks, 431.
at Lyme Regis, 281.
plutonic rocks of, 455.
and oolite, origin of, 282.
fossil plants of, 282.
Liebig, Prof., on conversion of coal into lignite, 333.
on preservation of fossil bones in caverns, 155.
Lima, recent strata of, 115.
Limagne d'Auvergne, freshwater formations of, 187.
Lime, scarcity of, in metamorphic rocks, 487.
Limestone, brecciated, 302.
crystalline, 302.
compact, 303.
fossiliferous, 303.
hippurite, 221.
indusial, Auvergne, 184.
of Jura, 261.
magnesian, 301.
mountain fossils of, 340.
primary or metamorphic, 465.
in Germany, of Devonian system, 348.
Lindley, Dr., cited, 223.
on leaves in lignite, 416.
Link, M., on footprints, 291.
Lipari Islands, rocks altered by gases in, 476.
Lisbon, marine tertiary strata near, 171.
Lithodomi in beaches of N. America, 78.
in inland cliffs, 73.
Llandeilo flags, 357.
Loam defined, 13.
Lochaber, parallel roads of, 86.
Lodes. _See_ Mineral Veins, 490.
Loess of valley of Rhine, 117.
fossil land shells of, figured, 120.
Logan, Mr., on coal measures of South Wales, 310.
on fossil forest in Nova Scotia, 322.
on reptilian foot-prints in lowest Silurian in
Canada, Postscript, viii.
London clay, 200.
Lonsdale, Mr., cited, 152.; on corals, 173.
on corals of Normandy, 170.
on corals in Wenlock formation, 355.
on fossils in white chalk, 26.
on old red sandstone of S. Devon, 345.
on Stonesfield slate, 266.
Louvain, Eocene strata near, 177.
Loven on shells of Norway, 114.
Ludlow formation, 351.
Lund, cited, 158.
Lycett, Mr., on shells of oolite, 266.
Lyme Regis, lias at, 281.
Lym-Fiord invaded by the sea, 33.
kelp in, 217.
Lyons, coal mine near, 319.
M.
Macacus, in Eocene formation, 203.
Maclaren, Mr., on erratic blocks in Pentlands, 125.
Maclure, Dr., on volcanos in Catalonia, 409.
MacCulloch, Dr., cited, 442.
on altered rock in Fife, 383.
on basaltic columns in Skye, 385.
on denudation, 67.
on granite of Aberdeenshire, 441.
on igneous rocks of Scotland, 390.
on Isle of Skye, 36. 456.
on hornblende schist, 478.
on overlying rocks, 8.
on parallel roads, 87.
on pebbles of granite, 460.
on trap vein in Argyleshire, 379.
Madeira, view of dike in inland valley in, 378.
Maestricht beds, 209.
Magnesian limestone, concretionary structure of, 37.
defined, 13.
groups, 301.
Maidstone, fossils in white chalk of, 214.
Mammalia, extinct, above drift in United States, 138.
extinct, of basin of Mississippi, 116.
fossil teeth of, figured, 160.
Mammat's "Geological Facts" cited, 69.
Mammifer in trias near Stuttgart, Postscript, xiii.
Mansfield in Thuringia, Permian formation at, 306.
Mantell, Dr., cited, 217. 229. 231. 251.
on belemnite, 263.
on chalk flints, 253.
on Brighton elephant bed, 257.
on freshwater beds of Isle of Wight, 198.
on iguanodon, 227.
on Wealden group, 226.
on reptile in Old Red, Postscript, x.
Marble defined, 12.
Marl defined, 13.
in Lake Superior, 36.
red and green in England, 289.
Marl-slate defined, 13.
Martin, Mr., cited, 250.
on cross fractures in chalk, 245.
Martins, Mr. C., on glaciers of Spitzbergen, 136.
Map to illustrate denudation of Weald, 242.
Map of Eocene beds of central France, 179.
Massachusetts, plumbago in, 478.
_Mastodon angustidens_, jaw, figure of, 159.
_Mastodon giganteus_, in United States, 137.
Mayence tertiary strata, 177.
Mediterranean and Red Sea, distinct species in, 100.
deposits forming in, 99.
Megalichthys in Cannel coal of Fifeshire, 336.
Megatherium in South America, 158.
Menai Straits, marine shells in drift, 130.
Mendips, denudation in, 68.
Metalliferous veins. _See_ Mineral Veins.
Metals, supposed relative ages of, 497.
Metamorphic rocks, 463.
defined, 8.
why less calcareous than fossiliferous, 487.
order of succession, 485.
glossary of, 466.
Metamorphic strata, origin of, 467.
Metamorphic structure, origin of, 477.
Meteorites in drift, 145.
Mexico, lamination of volcanic rocks in, 480.
Meyer, M. H. von, cited, 147.
on fossil mammalia of Rhine, 178.
on reptile in coal, 336. 337.
on sandstone of Vosges, 288.
on Wealden of Hanover and Westphalia, 237.
Mica schist, 465.
Micaceous sandstone, origin of, 14.
Microlestes antiquus, triassic mammifer, Postscr., xiv.
Miller, Mr. H., on origin of rock salt, 295.
on old red sandstone, 343.
on fossil trees of coal near Edinburgh, 321.
Minchinhampton, fossil shells at, 266.
Mineral character of aqueous rocks, 97.
composition, test of age of volcanic rocks, 399.
springs, connected with mineral veins, 496.
veins and faults, 488. 490.
of different ages, 490. 498. 499.
veins, pebbles in, 492.
subsequently enlarged and re-opened, 492.
veins, various forms of, 489.
veins near granite, 496.
Mineralization of organic remains, 38.
Miocene formations, 168.
in United States, 171.
period, volcanic rocks of, 415.
term defined, 111.
Mississippi, fluviatile strata and delta of, 115. 116.
Mitchell, Sir T., on Australian caves, 156.
Mitscherlich, Prof., on augite and hornblende, 369.
on isomorphism, 370.
on mineral composition of Somma, 404.
Modon, lithodomi in cliff at, 73.
Molasse of Switzerland, 171.
Mons, flexures of coal at, 53.
Mont Blanc, granite of, 453.
Mont Dor, Auvergne, 422.
Monte Calvo, section of, 18.
Montlosier, M., on Auvergne volcanos, 427.
Moraine, term explained, 123.
Moraines of glaciers, 141.
Morea, inland sea-cliffs of, 73.
trap of, 431.
Morris, Mr., cited, 177.
on fossils at Brentford, 147.
Morton, Dr., on cretaceous rocks, 224.
Morven, basaltic columns in, 385.
Mosasaurus in St. Peter's Mount, 210.
Mountain limestone, fossils of, 340.
Munster, Count, on fossils of Solenhofen, 260.
Murchison, Sir R., cited, 248. 324.
on new red sandstone, 290.
on age of Alps, 206.
on age of gold in Russia, 499.
on erratic blocks of Alps, 144.
on granite, 456. 459.
on primary strata in Russia, 124.
on joints and cleavage, 469. 471.
on old red sandstone of S. Devon, 345. 348.
on pentamerus, 353.
on Permian flora, 305.
on Silurian strata of Shropshire, 434.
on Swiss Alps, 484.
on term Permian, 301.
on term Silurian, 350.
on tilestones, 351.
Muschelkalk, 287.
N.
Naples, post-pliocene formations near, 403.
recent strata near, 112.
Navarino, lithodomi found in cliff at, 73.
Necker, M. L. A., cited, 445.
on composition of cone of Somma, 404.
on granite in Arran, 460.
on granitic rocks, 447.
on Swiss Alps, 484.
terms granite underlying, 8.
Nelson, Lieut., drawing of Bermuda, 79.
on Bermuda Island, 216.
Neptunian theory, 91.
Newcastle coal field, great faults in, 64.
Newcastle, fossil tree near, 312. 318.
New Jersey, _Mastodon giganteus_ in, 137.
New red sandstone, distinction from old, 286.
its subdivisions, 287.
of United States, 297.
trap of, 432.
New Zealand, absence of quadrupeds, 158.
Niagara, recent shells in valley of, 138.
Noeggerath, M., cited, 415.
Nomenclature, changes of, 93.
Norfolk, buried forest, 127. 130. 147.
drift, 126.
Normandy chalk, cliffs, and needles, 241.
Northwich, beds of salt at, 294.
Norwich crag, fluvio-marine, 148.
sand-pipes near, 82.
Nova Scotia, coal seams of Cape Breton, 315.
fossil forest of coal in, 321.
Nummulites, figures of, 200. 205.
Nummulitic formation, 205.
Nyst, M., cited, 176.
O.
Oeynhausen, M. von, on Cornish granite veins, 445.
Olot, extinct volcanos near, 408.
Old red sandstone, 342.
in Forfarshire, 478.
trap of, 434.
Oolite, 257.
and lias, origin of, 282.
inferior, fossils of, 272.
in France, 259.
plutonic rocks of, 455.
term defined, 12.
volcanic rocks of, 431.
Oolitic group in France, 283.
Orbigny, M. d', cited, 222.
on fossils of nummulitic limestone, 206.
on subdivisions of cretaceous series, 209.
Organic remains, criterion of age of formation, 98.
test of age of volcanic rocks, 399.
Ormerod, Mr., on trias of Cheshire, 295.
Overlying, term applied to volcanic rocks, 8.
Owen, Prof., cited, 155. 166. 229. 267. 268. 270. 291.
on amphitherium, 269.
on birds in New Zealand, 158.
on caves in England, 154.
on footprints, 298.
on fossils in Australia, 156.
on fossil monkey, 202.
on fossil quadrupeds, 157.
on ichthyosaurus, 276.
on reptile in coal, 337.
on serpent of Bracklesham, 199.
on snake at Sheppey, 201.
on thecodont saurians, 306.
on zeuglodon, 207. 208.
on reptile in Silurian rocks, Postscript, viii.
Oxford clay, 262.
Oyster beds, 204.
P.
Pacific, coral reefs of, 215.
Palaeontology, term explained, 103.
Palagonia, dikes at, 407.
_Paleotherium magnum_, figure of, 192.
tooth of, 193.
Palermo, caves near, 74.
Palma, Isle of, map and view of, 391.
Parallel roads, 86.
Pareto, M., on Carrara marble, 482.
Paris basin, 93.
Parkinson, Mr., on crag, 105.
Parrot, Dr. F., on salt lakes of Asia, 295.
Pebbles in chalk, 217.
Pegmatite, 440.
_Pentamerus Knightii_, 352.
Pentland hills, Mr. Maclaren on, 125.
Pepys, Mr., cited, 41.
Permian flora, distinct from coal, 305.
formation in Thuringia, 306.
group, term explained, 301.
Petrifaction of fossil wood, 39.
Petrifaction, process of, 43.
Philippi, Dr., on fossil shells near Naples, 113.
on marine shells in caves of Sicily, 154.
on tertiary shells of Sicily, 150.
Phillips, Prof., cited, 274. 309.
on cleavage, 471.
on terminology, 103.