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Straight, Rectis, as in most spars ; or
Crooked, Curvatis, as in Schiefer spar j or
Spherical, Sphcericis, as the mica hemisphaerica ;
Undulating, Undulatis, as in talc

Messrs. Wiedenman and Estner, there is an article under which several cha-
racters of the texture are given. Some of these I have arranged under this
article; others, under that of structure or compound texture. In Mr. Werner's
own work on the outward characters, this article does not exist."










Composed of thin layers or beds, as slat
i As the preceding was more peculiar to the
Slaty J crystallised, so is this to the rupestrious fos-

Schistosa ) sils. As this is rather a character ofmruc-
/ ture than texture, probably it might be
^- omitted here.

Scaly C Composed of a congeries of small scales. Pe-

Squ'amosa \ culiar to the plumbago, according to Estner.
Composed of a congeries of irregular crystal-
line parts, like coarse salt, as the coarser
Sparry ) kinds of scaly or saline limestone, as that of

Spfithosa j Sala in Sweden, some hornblende-schistus.
This belongs to the granulated of the Wer-
nerian school.

re In judging of the texture, attention must be paid, when
it is not of the compact kind, but of the fibrous or lamellar^
that it is inspected in a proper direction, which is that of its
parts ; otherwise, when in the opposite direction, the fibrous
may appear granulated, and the lamellar radiated."

Dr. Townson says that the structure is a particular dispo-
sition of the texture, as Hornblende-slate may have a sparry
texture and schistose structure; some iron ores, an earthy
texture and columnar structure. Of the Structure he only
indicates four kinds :

Slaty, Testaceous, Concentric, Columnar.
The first is too general, the three others too rare, to be of
real utility in a general system ; and this confined use of the
word Structure would interfere with its general use in other
senses equally appropriate.

The HARDNESS, another grand characteristic, may be best
illustrated in Werner's own words, which will at the same
time serve to convey some practical admonitions to the

ef After the particular generical characters discovered by
the sight in solid fossils, follow those which may be observed
by the feel, the first of which is hardness, forming the tenth
in the general system.


" Upon handling different fossils, we soon perceive (to
use, a familiar expression) that some are softer than others.
1 or instance, a piece of gypsum is much softer to the feel
than a piece o quartz. This difference is better observed
when we make use of some instrument fit for the purpose*.
This is what is termed by mineralogists the investigation of
hardness ; and, with respect to this property, we shall divide
solid fossils into hard, semi-hard, soft, and very soft.

"A fossil is called hard which cannot be marked or
scratched by the knife, or rather which emits sparks, being
struck by the steel. This degree of hardness is to be found
only in fossils which are perfectly brittle (Sprode). Hard
fossils are also distinguished into those which are affected by
the file; those which are but in a small degree; and those
which are not in the least. To the last belong the diamond,
ruby, and emerald; in the second may be placed the topaz,
rock-crystal, amethyst, flint, chalcedony, carnelian, &c. which
. yield a little to the file ; among those on which the file takes
effect, are white copper- ore, micaceous iron-ore, hematite,
most compact iron stones, red and brown tin crystals, most
shining grey cobalt ores (speis kobolt), arsenical and sul-
phureous pyrites, &c.

" Semi-hard is applied to a solid fossil which does not emit
fire with steel, and which may be marked or scratched by the
knife. Of this nature are fahlers, red copper-ore, sparry

* " The instruments employed by mineralogists in this investigation are, the
knife for semi-hard and soft fossils, the steel for those which are hard, nnd the
file for fossils perfectly hard. The knife may also be used to judge of the
streak and ductility. In order to possess a complete mineralogical apparatus, it
will suffice to add to these instruments a magnifier, which will often be wanted
to determine the exterior form and fracture, and which may be well observed
with a single glass; 2. a small phial of aquafortis, the use of which I shall dis-
close in the last chapter; 3. a loadstone, which for convenience may be so ma-
naged as to serve at the same time for a steel. If there be also added a blow-
pipe, in order to make essays speedily upon minerals with the assistance of fire,
we shall possess all to be desired. These articles may all be met with, well
made and adapted, at Mr. Schubert's, Mechanic to the Academy of Mines,

P !


iron-ore, hard earthy lead-ore, most blendes, white shining
cobalt-ore, native arsenic, kupfernikel, limestone, most cal-
careous spars and guhrs, fluor spar, zeolite, basalt, and many

" Soft solid fossils are those which are easily affected by
the knife, but receive no impression from the finger nail.
Such are white silver-ore, vitreous silver-ore, most red silver-
ores, vitreous copper-ore, mountain blue-ore of copper, most
bog iron-ores (Rosen eisenstein), galena, compact lead-ore
(bleyschweif) , white and green lead-ore, red phosphoric blende
(from Scharfenberg near Meissen), amber, heavy spar in bars
(Stangen spat), mica, asbestos, serpentine, &c. &c.

" Very soft is applied to all solid fossils which are not only
marked by the knife, but upon which the finger-nail makes
an impression. Of this kind are most solid cinnabars, cor-
neated metals, or native metallic muriats, micaceous bismuth-
ore, grey ore of antimony, most earthy cobalt -ores, cobalt
flowers, oxyd of native arsenic, realgar, native sulphur, mi-
neral pitch, most pit-coal, plaster- stone, glades marioe, talc,
black lead, most kinds of manganese, steatite ( Speck stein},
amianthus, chalk, &c. &c.

" But these different degrees of hardness are so apt to ap-
proach each other, that we find each of them not only of
many varieties, but very frequently observe fossils bordering
upon two degrees of different hardness, which varying a little

m both, forms a medium between these two degrees. For
example, hard magnetic iron-stone and opal, have nearly the
same hardness with semi-hard kupfernikel and basalt -, semi-
hard copper pyrites and malachite approach the soft heavy
spar and white lead-ore in hardness ; soft red silver-ore and
amber approach the very soft cinnabar and native sulphur.
It becomes therefore a matter of importance to determine the
hardness of a fossil, to indicate not the principal degree of
hardness alone to which it belongs, but also its relation with
known fossils of the same degree, and to observe when a
fossil forms a medium between two degrees. Thus, for ex-
ample, we shall say that fahlers, or grey silver-ore, is semi-


hard, but softer than copper f alders, and harder than copped
pyrites j that amber is soft, and forms a medium between
soft and very soft fossils."*

and TRANSPARENCY, which are described in the common
terms of most systems of mineralogy, it may be necessary to
add a few words concerning the other remaining character-
istic, namely, the WEIGHT. In this, as already mentioned, Weight,
a relative scale is proposed, instead of ciphers, which seldom
supply prompt or immediate ideas, especially as the reader
generally forgets the tables prefixed. The total dismission of
ciphers serves, at the same time, to render the arrangement
more uniform and harmonious. The Weight has been, by
ttiany of Werner's disciples, confounded with the Specific
Gravity, which requires an operation, and does not belong to
the external characters of Werner ; while the Weight, with
some experience, may be estimated, as he says, by the hand.
His epithets, however, are in this instance particularly indis-
tinct, being Very light, Light, Rather heavy, Heavy, Very
heavy. His scale is also too brief, five degrees being neces-
sary for the gems and rocks, and five more for the metals.
For while the specific gravity of platina is about 21, gold 19,
silver 10, copper 8, iron about 7, and tin little inferior,
barytes only exceeds 4 j so that there is a wide transition from
the heaviest stones to the metals, but not so great to the ores.
To the metals, therefore, another scale should be adapted for
common use. It is hoped that the one here proposed will be
found sufficient for the purposes of petralogy ; and it is, like
the other improvements, submitted to the discussions and
''alterations of the intelligent in a science which is quite new
and daily progressive.

^ 3. Remarks on Werner's Geognosy, or System of Rocks.

From the sketch imparted by Daubuisson to Brochant,
and from Mr. Jameson's Geognosy, we are enabled to form an

* Werner, Ch. Ext. p. 2/2.




idea of Mr. Werner's system concerning the formation of
such parts of this planet, as we can hope to observe, little
exceeding the three thousandth part of its semi-diameter. I
warmly subscribe to the sentiments of admiration which are
paid to Mr. Werner's superior talents in many branches of
mineralogy, a science infinitely indebted to his industry and
sagacity. I also acknowledge the truth of the apophthegm,
Natura fecit omnesjudices,paucos artifices. But I regret, with
his most enlightened admirers, that the scene of his inquiry
has been too confined j and that his view of the mountains
of Saxony has not been extended over the globe. After forty
years of sedulous observation among the Alps, Saussure, who
began his labours with a view of forming a system, declares
that his hopes were frustrated -, and that he had met with
such unaccountable confusion that he could not venture to
propose a theory. Yet Saussure, to practical observations on
a far superior scene, added the advantages of learning, and
mathematical and meteorological science, which Mr. Werner
unhappily wants, and which would have corrected and greatly
improved his speculations.

After describing the general appearance of the surface of
the earth, and the effects of water, he proceeds to consider
the structure of rocks, in their minute parts, and in their
general fabric j the latter chiefly consisting of the stratified
structure, and that with seams, in which last he includes
Formations, columnar basalt. His grand doctrine of formations next
appears. When the mass is uniform, as in granite, gneiss,
limestone, the formation is said to be simple ; but when dis-
similar masses occur, as of coal and basalt, it is called com-
pound. When the formations consist of several substances** H
always found together, though in regions of different compo-
sitions, they are all called independent formations j but
when only associated, they are called subordinate. The uni-
versal formations are found all over the globe $ but partial or
anomalous formations are confined to particular spots. De-
Other terms, tached portions on the summits of hills are called caps ; but
when a part appears only on one side of a mountain, it is



said to form a shield. When the superior strata have the
same direction with the fundamental rock, they are said to
be conformable with it ; but when the direction is different,
they are called unconformable. Sometimes they are simply
unconformable, as differing only in direction , but when in
addition to this they pass over the terminations of the inferior
rock, they are said to be unconformable and overlying.
Strata may also be strait, form a mantle around the inferior
rock, cover its extremities in the shape of a saddle ; or,
when concave, assume the form of a bason or a trough.

Considering Mr. Jameson's work as notes taken during
Mr. Werner's lectures, it may be assumed that this illustri-
ous mineralogist then proceeds to consider the succession of
the different formations. Those rocks which are always
found inferior, are called Primitive ; and have a crystalline
appearance, intimating a chemical solution, when the water
ood very high over the surface of the earth. The next
class is called Transitive ; which, though chiefly of chemical
composition, exhibits also mechanical sediments and petri-
factions. The third class consists of Stratified rocks, styled
by Werner Floetz, signifying that they are in flat or hori-
zontal layers or beds ; a stratified rock implying that the
strata are of one and the same substance -, while the Floetz,
or rocks in layers, often present beds of different substances.
But this distinction is not of such utility or importance as to
necessitate the introduction of a barbarous word; and if
stratified be not precise, we may use stratiformed with Dau-
buisson. The Alluvial and Volcanic rocks form the last

It is to be regretted that the examples and facts are not
sufficiently numerous, but even the primitive rocks seem all
to be regarded as stratified, except granite, which is assumed
as the universally radical rock. In the Alps, Saussure has ob-
served that the granite presents marks of stratification.
Gneiss is also found under primitive granite ; and Mont Rosa,
nearly equal in height to Mont Blanc, consists chiefly of
gneiss and other stratified rocks. After long and diligent







inquiry, the position that granite is the universally radical
rock, would appear to be rather an assumption founded on
theory, than a fact supported by proofs ; for if we examine
the accounts of the substances found at the greatest depths,
in coal mines and other excavations, there is no appearance
of granite j and ,if lavas often arise from a vast depth, a fact
now admitted from the prodigious extent of the preceding
earthquakes and other phenomena, the chief substance is iron
mixed with clay j and the mineralogical appearances tend to
confirm the opinion of astronomers and natural philosophers,
jTthat the nucleus of this planet consists of iron ; which, even
when native, is seldom found unmixed with silex, so that if
any rock can be called fundamental, it must consist of such
a mixture. It is true, that granite itself presents such a
composition, as iron is found in the mica, and still more in
the siderite, which in the oldest granites often supplies its
place j and what is chiefly to be regretted, is the want of
positive proofs concerning the anteriority of granite.

Werner proceeds to explain the effects of the gradual and
slow diminution of the primeval waters, in producing chemi-
Dissoiutbns cal dissolutions from a great height, and afterwards gradual
and sediments. sediments . so thatj accor <]ing to his theory, the shell of this
globe, instead of presenting a ruinous and unaccountable
confusion, exhibits, when viewed on a large scale, a regu-
larity and harmony, such as are admired in the other works
of the great Creator.

Having thus briefly explained this celebrated theory, it
must be added that the rocks are divided into various forma-
tions, which often receive arbitrary and unexpected epithets.
Sequences. Thus the series called the SLATE FORMATION, is so named
from the central member SLATE, rising to mica slate, and
passing from gneiss into granite ; while, on the other hand,
Objections. llae descent ends in coal, sand, and elay. It must strike every
enlightened observer, that such a distribution, instead of
leading to a just and accurate knowledge of rocks, as they
occur in different parts of the world, would only form an
illustration of the Wernerian system 3 which may, in the



progress of discovery, be found, like preceding systems,, to be
essentially erroneous. If a work of petralogy were there-
fore founded upon this theory, it must fall with it : and no
writer of judgement or industry would choose to risk his
labour upon such an uncertain foundation. Nay, if the
theory were invincible, the arrangement would still be im-
proper for a student of petralogy j who must follow the best
mineralogical authors, and arrange substances according to
their chemical compositions, and other infallible rules arising
from the nature and appearance of the substances themselves,,
whether they exist in nature or in cabinets. A general
treatise on rocks therefore cannot be founded on any theory
of their formation, however plausible ; as the opinions of the
author will be biassed by that theory, and he will be inclined,
like Buffon, to reject or pass in silence any substance which *
interferes with his preconceptions. Thus jasper is totally
omitted by Werner, though it form a chain of mountains in
Siberia, of more than a thousand miles, extending even to
the islands between that region and America. A disciple of
Werner is therefore embarrassed when he sees specimens of
rocks, not disposed in a theoretical sequence j and, in his
vindication, boldly asserts that rocks can only be studied in
nature, where the formations indicate the series of substances.
But as this argument would be ridiculous if applied to litho-
logy, or the knowledge of small or precious stones, so it i&
equally inapplicable to petralogy ; the distinctions between
large stones being as certain, and still more useful to society.
The knowledge of small and precious stones has been accom-
panied and greatly assisted by the constant introduction of
new denominations, which at present amount to about two
hundred j while the rocks of Werner do not exceed sixty,
although the distinctions between the rocks be not only
more numerous, but more apparent than those between the
parasitical stones. If the systems of botany and zoology
were founded on progressive formations, it is evident that no
two authors could agree upon the links of the chain j and
such systems have accordingly been founded upon character-


istics derived from their exterior forms ; while, in mineralogy,
the forms of the greater masses being casual and uncertain,
recourse must be had to chemical analysis, as well as to exte-
rior qualities. But, in the former, it is not so much the
substances forming the combination, as the mode or manner
of that combination, which constitutes the essential differ-
ence among the objects of mineralogical knowledge ; for the
diamond is only a modification of coal, and the sapphire of
clay and iron rust. Hence, while the mode of the chemical
combination establishes the most essential difference, the
structure and the aspect constitute more minute distinctions.
It may also be observed, that Werner's method of distin-
guishing rocks, by their formations and positions, seems at
variance with his treatise on the external characters of mi-
nerals, in which the science is rightly founded on its only
firm foundations, those depending on the characteristics of
the substances, as considered in themselves. This object was
perhaps considered by Werner as already accomplished in that
treatise, and in his lectures on Oryctognosy, or the general
knowledge of minerals : but the rocks form a class so im-
portant and distinct, that they deserved a separate considera-
tion, before proceeding to the bold design of general geo-
gnosy or geology. Perhaps the experience and observations
of two centuries may still be wanted, before such a design
can be reasonably attempted ; and at present the Huttonian
system has as many admirers as the Wernerian, though
founded on principles totally opposite : but, in all events, it
was necessary to begin with an elementary work, containing
all the erudition already acquired on the subject, leading to
more clear and precise views, or exact distinctions, and a
Necessity of consequent increase of denominations, without which even

new names and theory must be embarrassed: for at present it is not even

agreed what object precisely constitutes granite, and what

object basalt. All theories, however, tend to the advance-
ment of science, by stimulating inquiry and discussion -, but
it is clear that the theories must be vague, and the contests
alike fruitless and endless, till the parties shall have agreed


upon the denominations and definitions. For what hope of
any reconcilement of opinions, or any clear knowledge, when
the French persist at this moment in regarding basalt as com-
pact lava 5 while Dolomieu, the greatest of their mineral-
ogists, and at the same time a practical and sedulous observer
of volcanoes, has loudly declared that the basalt of the an-
cients is never a volcanic product ;

Petralogy therefore, or the knowledge of rocks, must., like
the other branches of mineralogy, be studied in cabinets as
well as in nature -, and in the substances themselves, not in
supposed theoretical positions : for if the student cannot dis-
tinguish a rock without these adventitious aids, which in the
great variety of nature will themselves often lead to false
conclusions, he may be pronounced as truly ignorant of the
subject, as he who cannot distinguish gems without being
informed of their countries, sites, and gangarts. And this
would be the more absurd as it is self-evident, as already ob-
served, that large substances must present more palpable and
more numerous distinguishing characteristics than the

It must also be considered that Werner, by founding the
knowledge of rocks on a system of geognosy, has been led by
juxta-positions, and other accidental circumstances, observed
in the confined scale of Saxony, to diminish rather than to
enlarge the number of denominations ; the result of which
practice would evidently be to obstruct the progress of the
science 5 and, as he is not versed in erudition, his own deno-
minations are sometimes unclassical, and so vague, as to give
no positive idea; of which examples may be found in his
flinty slate, his slate porphyiy, and his white-stone. Indeed
his new denominations in lithology being often founded on
colour, have been sometimes rejected*. To institute new de-
nominations, it is evident that erudition is necessary j and
this leads me to observe, that the study of preceding works

* When he classes the gems as siliceous, instead of argillaceous, he confounds
them with the false gems (rock crystals, &c.), which are siliceous.






on the subject is indispensable to a complete treatise on pe-
tralogy, which should enable the student not only to know
the substance, but the denominations used by former mine-
ralogists and travellers, and by historians, philosophers, and
poets, which will not only enlarge his ideas but give him
more accurate knowledge. And as few of the sciences can
be founded on personal observations, vita brevis, ars longa,
and the brevity of human life will not permit a petralogist to
pass forty years in the Alps with Saussure, thirty in Saxony
with Werner, &c. &c. he will of course acquire infinitely more
knowledge by the study of their works, than by any personal
observations j so that this science, like all others, results
from accumulated knowledge.

These observations shall be concluded with Werner's ar-
rangement of the rocks.


1 Granite.

2 Gneiss.

3 Mica Slate.

4 Clay Slate.

5 Primitive Limestone.

6 Primitive Trap.

7 Serpentine.

Primitive Rocks.

8 Porphyry.

9 Sienite.

10 Topaz Rock.

11 Quartz Rock.

12 Primitive Flinty Slate.

13 Primitive Gypsum.

14 White-Stone.


1 Transitive Limestone.

2 Transitive Trap.

3 Grey Wacke.

. CLASS III. Floetz or Stratiform Rocks.

Transitive Rocks.

4 Transitive Flinty Slate.

5 Transitive Gypsum.

1 Old Red Sandstone, or

first Sandstone Forma-

2 First, or oldest Floetz


3 First, or oldest Floetz


4 Second, or variegated

Sandstone Formation.

5 Second Floetz Gypsum.



6 Second Floetz Limestone.

7 Third Floetz Sandstone.

8 Rock Salt Formation.

9 Chalk Formation.

10 Floetz Trap Formation.


1 Peat.

2 Sand and Gravel.

3 Loam.

4 Bog Iron Ore.

1 1 Independent Coal Form-


12 Newest Floetz Trap


diluvial Rocks.

5 Nagelfluh.

6 Calc-tuff.

7 Calc-sinter.

1 Burnt Clay.

2 Porcelain Jasper.

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