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F. A. Ckntk's CcfUributiam to Mineralogy. 251



I fbnnd the pure mineral to contain :








Silicic ftcid, • - - S4-90


ooDtaiu


12*92 oiygeo


= 1*20


Alumina, • • - 21*77


M


1017


11*66


1*08


Sesqubzyd of iron, • 4*60


«


1-88


Oxjdofinm, • - S421


M


6*87


. 10*74






m


0*26


I-


Mfigneaia, - "^ • > 1278


M


611,




Water, .... lu-6f


m


9*41




0*87



The oxygen ratio of RO : R, 0, : Si 0, : HO being

1 : 108 : 1-20 : 087, the ratio of the
equivalents would be ssl2 : 4 : 6 : 10, and oonsideriog
alomina and sesquioxyd of iron as replacing silicic acid the

formula =8^4(2 L+iofl, or perhaps better =ft4(|*),+8fl;

9. PhoUriU.

A mineral has been observed in several of the coal mines of
Schuylkill county. Pa., under similar circumstances to those,
under which phdlerite has been found in France and Belgium,
that, their physical properties being the same, I consider them
identical, notwithstanding the differences between my own and
Ouillemia's analyses;

At Tamaqua it is found in scales of a velldwish white color,
which, however,- can be easily removed by dilute chlorhydric
acid, and near Po^tsville in sno^ white' nacreous scales of a
p^rly lustre.

Under the microsoope the scales appear to be clinorhombio
with the planes tl predominating and -It indicated by the trun«
cation of the acute basal edge of the right rhomboidal prism.

I have made several analyses of the mineral from Tamaoua,
both in its original state and after purifications by dilute chlor-
hydric acid.

The analyses were made by fusion with carbonate of soda, as
well as with concentrated sulphuric acid ; the silicic acid separa*
ted by the latter method dissolved completely in boiling carbon-
ate of soda. The alkalies were determined by J. Lawrence
Smith's method :

X. n. ra. IV.

Original MIoeraL Bxtraeted b^ Chtorhydrii Aetd. Cakolated.

BjrNaO.OOa ByNaOOO, ByHOSO, SI9 814488

Snicio icid, » 46*98 46-9S 46*81 47*<»e

Alumina. 87*90 89*66 8956 8920

Seitqaiozjrd of iron, 18 -— —

lime, - - 0-98 —

fkKk. - • )Natdet«r- O-lt

PuUiih, • • ) mined. 006

Water, 18 98 18*69

99-98 1U049

These analyses show that many of the varieties of the so-oaUed
Icaolin belong to pkoletite.



0*11




006




18^


18*71


10045


lOo-oo



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292 F. A. €fenth's Cantribntiom to Mineralogy.

10. SeheeHte.

I have observed in North Carolina several new localities of
this mineral.

a. At the so-called Dutchmen Vein of the Bangle mine prop-
erty, Cabarras county, it has been met with between 90 ana 100
feet depth, associated with pyrites and chalcopyrite in quartz ;
forming an ore, which contains from 2 to 3 ounces of fine gold
in 2000 pounds. Although it is considerably disseminated
through the whole mass of ore in fine grains, the largest masses,
which I have seen were not over f ths of an inch in diameter.

No crystals have been noticed, but only granular masses of
a pale yellowish brown color, distinctly showing the octahedral
cleavage. It contains :

BiDOzjd of tin, - - - 0*lt

TuDgstio tdd, ...... 79-69

Oxjd of copper, ♦ . . . . 008

Se^quioxjd of iron, - • • - (MS

Lime, 19 SI

99*2i

6. Another locality is at the Flowe mine, Mecklenbnrgh
county, N. C, where it is associated with barytes, clialybitOi
pyrites, chalcopyrite, wolfram and rhombic tungstate of lime.

Not more than two crystals have been observed ; the first be^
ing a modification of the octahedron 1, slightly truncated by lu
It has a yellowish brown color and would, if perfect, have a
length of tV of one inch ; the other crystal was about half that
size, had a fine orange color and was a combination of the planes
i and it; it contained a small quantity of tungstate of oaryia.
Both crystals gave B.B. traces of tin.

11. Rhombic Tungstate of Lime,

Found also at the Flowe Mine.

It has a yellowish and greyish white color, and a vitreous loi^
tre, which is subadamantine on a fresh fi*actnre.

The crystals are small and indistinct, an aggregation of manj
individuals frequently formed into one crystal ; the largest one,
which I have seen, but which was very imperfect, was Jth of an
inch long. All crystals contain a nucleus of wolfram. I have
noticed the following planes : ^ n, ^, 1 and It; cleavage could
not be observed.

Are these crystals psendomorphs? I do not believe it, at any
rate, they have not the appearance of psendomorphs. We know
that lime is isomorphous with oxyd of iron and manganese, I
would therefore suggest that tungstate of lime is dimorpnous^ and

that in this case it is coating a nucleus of (j£^)Of WO,, just

like a chrome-alum crystal, when placed into a solution of alum,



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F. A. Oenih's Contributions to Mineralogy, 25S

deposites upon itself a coating of the latter, or in the same man-
ner, in which the green tourmaline, of Chesterfield, Mass., sur-
rounds a nucleus of the red. I do not think that ever anybody
considered the green a pseudomorph of the red one ?

12. Wolfram.

I have examined the wolfram, which forms the nucleus of the
rhombic tungstate of lime.

Only one crystal has been observed yet, which shows the
planes /, it, ^i and IJ. Sp. grav. at 25° Cels. =7-496. It contains :

Tongvtic acid, - ..-. 76*79
OzydofiroD, -..-.. 19*80

Oxyd of mangaiiMe, ..... 535
Lime, - -.... 0-82

Binozjd of tin, • • - • - - trace

101*26

This corresponds with the formula : 4FeO, WO,-|-MnO, WO,.
13. A few observatums on the occurrence of Gold,

Much has been said and written about the occurrence of gold
in veins and elsewhere and the formation of the same, but com-
paring the different theories with some venr important facts, we
are often at a loss to explain the latter satisfactorily, and it seems
to me that we know but very little about this difficult subiect.
Without anjr intention to discuss the merits of the different theo-
ries, I will give in the following a few data, which may help to
throw some light on this question.

Oold is frequently found in diorite (in smaHer Quantities in
syenite and granite) and although it is only rarely ^observed in
the massive rocks, I have seen specimens from Honduras, C. A.,
where it was imbedded in the diorite without any other associa-
tion. The result of the complete decomposition of the diorite is
generally a red clayish soil and this ha& in the gold region of
Korth Carolina, etc., a high reputation for its ricnness in eold.
It was in the diorite region of Cabarrus County, N. C, where
the first large piece of gold was found, weighing twenty-eight
pounds. All this soil is more or less auriferous, out containing
the gold somewhat concentrated, nearly in the same ratio, in
which the lighter particles have been washed away. But not
only in this country the diorite has been found to be auriferous^
as is proved by the large piece of eighty-six pounds which was
found at Alexandrowsk near Miask in Siberia, nine feet below
the surface, in diorite.

The gold obtained from the disintegrated diorite is generally
smooth and rounded as if it was water-worn. This cannot be,
however, because it lies still in its original, but only altered
matrix, and has not been subjected to any attrition by water and



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t254 F. A. Genih's Contributions to Mineralogy.

Band ; besides, if we observe any cavities in sucb ^Id, we find
tbe sharp edges of crystals, etc., in the same, rounded in a simi-
lar manner, jost as if the whole piece had been subjected to the
action of acids, which in reality seems to have been the case. I
believe that this is the most natural explanation, because it tells
us at the same time, to what source we must trace the gold,
which we find in the veins passing through these formations.

The greatest difficulty presents itself by inquiriug into the
nature of the solvent. 1 do not believe it is very probable that
the gold has been carried off as a silicate of gold, or by the action
of chlorhydric acid upon the sulphid. What seems to me most
reasonable^ is that it was dissolved as terchlorid of gold. If we
remember, that the decomposition of pjrites, one of the most
commdn accessory constituents of dionte, produces sulphuric
acid, which in the presence of the never wanting chlorid of
sodium and an higher oxyd of manganese may liberate small
quantities of chlorincj the most pd^^erful solveitt of gold, we have
at least a very plausible explanation.

After penetrating the decomposed diorite the solution of gold,
pacing aowii the veins, comes in Contact With reducing agents
and is repreclpitated again, freaaently in crystals or crystalline
forms. I shall fiirther below make a few remarks about the sub-
stances which precipitate the gold, in veins as Well as in beds.

An almost positive proof that the eold in the veins of the
diorite formation originates from the adjoining rocks is the fact
that the deepei* the diorite is decomposed, the deeper the gold is
found in the veins. Many of these veins do not contain any
gold at fifty feet depth, and I have kndwn veins, which were
rich near the surface, not to c6ntain a trace of gold at thirty-five
feet depth. Very few of these veins (if not on high hills) carry
sinv gold below 120 feet depth.

The occurrence of gold in beds in the metamorphic slates at
grettt depth can fai' more be relied upon ; Gold Hill, in Bowan
Co. Ni C, for instance, is over 600 feet deep arid the ore as rich
as ever* Although it cannot be denied that the greater portion
of the gold in such deposits is as old as the stratum itself, in
which it occurs, it is certain that inside of such auriferous strata
constant changes are going on, gold dissolved and reprecipitated.
We could not account for the crystalline structtire of most of the
gold in such beds if we would not presume that the freshly pre-
cipitated gold deposits frequently upon that already present

The description of a few specimens in my collection may be
interesting, tor they prove that the gold must have been in
solution.

a. From Whitehall, Spotsylvania Co. Va., — shows gold asso-
ciated with tetradymite, limonite and quartz. The gold is crys-
tallized in forms' belonging to the i^hombohedral system and



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F. A. (tenth's ConirUfutions to Mineralogy. SS5

sliowinff very distinctly one rhomboliedron, scalenohedron and
basal plan ; it is coating tetradymite and evidently a pseudo^
morpb after it. I have seen other specimens from the same
locality, but of inferior value and beanty.

6. The tetradymite from the Tellurium Mine, Fluvanna Co.
Ya., and the native bismuth from the Peak of the Sorato in
Bolivia, S. A., are frequently interlaminated with gold.

I bave made some experiments with a solution of terchlorid
of gold and tetradymite and found that the latter precipitates
the gold £rom a dilute solution easily with a smooth and brilliant
surface.

c. In the upper portion of the ore bed in the metamorphio
slates at Springfield, Carroll county, Md., which, near the sur-
face, consists of magnetite and at a greater depth of chalcopyrite
and other ores, sometimes films of native gold bave been ob*
served coating the cleavage planes of magnetite. On close ex-
amination it can be noticed that below the film of gold tbe mag-
netite is oxydized into hydrated sesquioxyd of iron.

d. A very striking occurrence of native gold is, that where it
is associated witb pyrites. Most of the pyritous gold ores are too
poor to form a positive opinion about the form, in which they
contain the gold, from observation, and many authors are of
opinion that tne gold may exist in the form of a sulphid, either
by itself or as a sulphosalt. If we take it for granted that the
pyrites itself is tbe result of the reduction of iron-salts and bear
m mind that protosalts of iron reduce gold tnstarUaneausly, we
cannot adopt this opinion. But even if terchlorid of gold should
have been precipitated by sulphydric acid, whilst passing
through the vein, it could not remain in that state for a long
time, because moist tersulphid of gold in the presence of the
smallest trace of an acid is easily decomposed into metallic gold
and sulphuric acid. Some specimens of auriferous albite from
Winters vein, Calaveras county, Califi)rnia, show beautifully
that, wherever there is a crystal of pyrites, small crystals of gold
are attached to it, demonstrating, tnat the sulphate of iron pre-
cipitated the gold, previous to its own reduction into pyrites.

All these mcts prove that the gold is carried into the veins
from the adjoining rocks, and that the opinion, which considers
veins the source of the gold of alluvial and diluvial deposits and
the soil, is erroneous.

K another proof was wanted to show the fallacy of this idea,
it would be the &ct that the gold from the soil or alluvial and
diluvial deposits, has rarely the same fineness as that from the
veins wrought in the immediate neighborhood of the same, the
latter being generally less fine. It is impossible therefore that
the destruction of a portion of these veins could have furnished
the gold of such deposits.

Philadelphia, July 27, 1869.



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856 LsUerfrom Sir R. I. Murchison oH



Art. XXXI. — Notice of a Memoir by M. Julea Marcou, entitled
" Di/as and TVias or the New Bed Sandstone in Europe, North
America and India,^^* (la a letter fjx)m Sir BODERICK I.
Murchison to the Editors.)

Gentlemen —

In the early part of last winter I read with surprise the fol-
lowing paragraph in a published letter by M. Jules Marcou on
Amencan Geology. " 1 think that the term Permian, at least
as given by Murchison for the strata of the government of Perm,
a very improper one. There are strong suspicions that Murchi-
gon has put into his Permian a part if not the whole <rf the
Trias, and I am almost certain that if .geologists accept the Rus-
sian Permian as Murchison has defined it as the type, the Trias
will disappear from classification in Asia, Africa, America, and
Australia.

Considering this to be a serious charge, I wrote to M. Marcou
and begged to know the grounds on which he had made it. As
he had never been in Bussia, I called his notice to another ex-
pression in his own letter on American geology in which he
says: "not having visited Kansas or Nebraska I have no de-
ciaed opinion respecting the geology of those countries; for I
profess the doctrme that geologists must see with their own
eyes," &c. I further expressed a wish, that M. Marcou had
acted on his own doctrine, as respected Bussia, before he passed
so severe a judgment on the researches of M. de Verneuil, Count
Keyserling and mysel£ The replies sent to me by that gentle-
man, though very polite, being by no means satisfactory, I
stated to him my intention of publishing our correspondence in
your journal. But I abstained to do so until M. Marcou had
produced a fuller explanation of his views.

Afker a study of the original work of my friends and self, M.
Marcou has at length produced his results in the.Bibliothdque
Universelle de Geneve under the title of which a translation i»
given at the head of this letter.

Leaving my able contemporaries in America and the Geologi-
eal Surveyors in India to settle their accounts with M. Marcou,
I have requested my coadjutor, M. de Verneuil, to answer this
article in tne French language. In the mean time I confidently
refer the judgment of the value of this critical essay to all geolo-
gists who have followed the progress of their science.

All such j)ersons know, and particularly those who have read
the new edition of my work on Siluria, lliat the absolute distinc-
tion between the fossils of the Permian group or Di/tu of M.
iMarcou and those of the Trias is much more sharply defined

^ Bibliothdqae IJniyenelk de Gendre, Mai et Jain, 1869.



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Mr. Jules Marcim't Dyoi and Tria$. S57

tban ever, and yet he reverts to the former and obsolete state of
the science and merges these two most markedly separated de-
posits in one natural groap. The author applies his new word
'Dyas' to the rocks in question because the two deposits only of
Botbe-liegende and Zechstein chiefly prevail in certain tracts;
but geologists who have gone through all the proois I have ad-
ducea from various countries of a clear division of the Permian
rocks into three parts, of which Zechstein is the centre, will not
easily be led to adopt the use of the new word — still less to mix
up as proposed the Dyas and Trias in one geological group.

Although I will not answer objections in detail on the geology
of Russia which proceed from a writer who has never been in
that country, let me inform those of your readers who are in
the same condition as M. Marcou, that one of the very reasons
he assigns to depreciate the correctness of my ultimate classifi-
cation, ought to operate in my favor. It is quite true that in
most parts of the vast region of Russia (larger than France) oc-
cupiea by the rocks to which I assigned the .name of Permian,
ther;e is no large development at their base, of those deposits
which in Germany are known as the Roth-todt-liegende, though
even in Russia there are tracts in which underlying grits with
plants represent that German deposit But the great fact which
1 established b^ visits to all the classical districts of Germany
before the publication of the work on Russia and by comparinff
them with those of Russia is, that whether the pebble-beds and
sandstones underlie the Zechstein as in Germany or are inter-
mixed with and chiefly overlie all the limestone as in Russia^
the plants of the two regions have been pronounced to be iden-
tical. These plants are related generically to the Carboniferous
forms, whilst on the authonty of Goppert they are pronounced
to be entirely distinct from those of tne Trias.

In short, the whole geological series does not offer a more
complete discordance or type between any two conterminous
groups than that which exists between the fossils of the Per-
mian and those of the Trias, whether we refer to their respect-
ively imbedded reptiles,, fishes and shells, or to their plants ; the
one set marking the close of Palaeozoic, the others the corn*
mencement of the Mesozoic era. Yet these are the two deposits
which M. Marcou unites in one natural group under the name
of New Red Sandstone.

To conclude, let me request you, Messrs. Editors, to have the
goodness to translate into English the concluding page of the
memoir of M. Marcou, beginning " En resum^" &c., and I will
then require no other reason to induce plain geologists to side
with my associates and self, by retaining in the great palaeozoic
division of life, the inhabitants of the Permian era, and by op-

tfCCOND BERIES, Vet. ^XVUI, No. Sl-SKPT., I860.
33



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258 Letter Xrofn Sir R. I MureMson on Marcou's Dyas, etc.

posing the views of an author who considers such fossils to be
the remains of ** precocious beings" — ^the * precursors' or * ad-
vanced guard' of the secondary or Mesozoic populations!"
I remain gentlemen, your very obedient servant,

KODEEIOK I. MUBCHISON.
Oeologicfd Survey Office, Loodoo, July 26th, 18S9.

P. S. — Informing his readers that my eminent friend M.
d'Omaliqs d'Hallov had named the s^me rocks Penifen ('poor*)
which I afterwards termed Permian, M, Marcou should recol-
lect, that when I wrote my first letter on the subject to Dr.
Fischer ftt Moscow in 1842, 1 was far distant from any works of
reference. When, however, I consulted the * Elements de GA>1-
ogie' of (J'Omalius, published in 1831, I found that although
that sound geologist had widely separated his * Penmen' from the
^ Terrain Kuprique,' he still maintained as a part of the group
the * New Red Sandstone,* from which the Permian was specially
distinguished. Moreover, I much preferred a purely geograph-
ical name taken from a country where fossils abounded, to a term
which implied poverty of fossils. Jri fact, M, d'Omalius tells us
(p. 276) that his name Peu6en was intended as a French transla-
tion of Robt-todt-liegende, the examples of which rock, best
Jcnown to the Nestor of Belgian geologists, near Malmedy, are
indeed quite sterile, as X know from personal examination long
before I visited Russia.

The following is the summary of Mr Marcou, called for in
the last paragraph of Sir R L Murchison's letter, — Eds.

" To sum up, I am led to regard the New Bed Sandstone com-
prising the Dyas and Trias as a great geologic period, equal in
time and space to the Palaeozoic epoch, or the Gray wack& (Silu-
rian and Devonian), the Carboniferous (the Mountain Limestone
and Coal Measures), the Mesozoic (Jurassic and Cretaceous),
the Tertiary (Eocene, Miocene and Pliocene), and the recent de-
posits (Quaternary and later). I also restrict the limits ordina-
rily ascribed to the Palaeozoic and the Mesozoic, and give them
proportions more in harmony with those of the Tertiary and re-
cent epoch — to the end that we may have a well balanced and
natural classification.

**In the ' New Bed' as well as in all other great epochs, we
remark that the lower beds, (the l^othrliegende) contain Car*
boniferous forms of life — a kind of ^rear guard^ of the popula-
tions whose destruction had commenced, indicating that there
were some organisms endowed with a vital force superior to that
given generally to other beings, permitting them to witness the
disappearance of all their contemporaries, and at the same time
to become the spectators — but isolated spectators^ of the advent of
new generations, which, although composed of beings somewhat



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C. U. Shepard on a Meteoric Iron? from N. Carolina. 269

similar to their predeeessors, are endowed nevertheless with
other form& and of necessity therefore with other habits, asso-
ciations, and aspects — exactlr like the centenary in our human
societies. On the other han(), the upper beds of the New Ked,
such as the *HalstatterKalk,' the 'RaiolerSchichten,* the 'Bone-
bed,' or the Keuper contain forms indicating the approach of
another geologic period of secondary beds (Jurassic and Cretace-
ous), beings which Professor Quenstedt has happily designated
as the ^precursors' or ^ advance guard' of the Mesozoic popula-
tions. Precocious beings, these precursors, recalling generally
by their sudden appearances and disappearances, those comets
which coming from time to time announce that greatevents are
on the point of fulfillment. Or, better still, they may be com-
pared to plants which, forced in hot-houses, flourish in the win-
ter, in place of awaiting the spring and whose pale-tmted flow-
ers, ana etiolated or disproportioned forms, appear as if they
^new that they were before their time, and as if it was only a
eipecies of tentative experiment, which they were performing and
so they hastened to aisappear to make room for the vigorous
and abundant flora of the warm season."— AWiotfi^yuc Univer-
sells {de Oetiive), Juin 20, 1869^ pp. 145, 146.

[Obs, It will be interesting for the reader to t\Jm from Mr.
Marcou's "rear guards, isolated spectators," and "advance
guards," to the plain prose of facts observed by Dr. Newberry in
New Mexico, on the site of oui' author's assumed Jurassic beds.
See p. 298.]



Art. 'XXXtt— Examination of a supposed Meteoric tron^ found near
Ruiher/ordton, North Carolina; by CHARLfiS VfUam Shepard.

For mv first knowledge of this Iron, I am indebted to Dr.
Thomas S. Duflfy of Rutherfordton, who in the winter of 1857
casually mentioned to me at Charleston, that he had been shown
a verv remarkable specimen ol an ore found in hip vicinity, of
the character of which no one had been al^le to pronounce a
satisfactory judgment From his description of its lustre and
color, and of certain striae on one or more sides of the mass, I
conceived it might prove a large crystal of mispickel. He
was kind enough on his return home to send me in a letter,
a few grains that had been chipped from the mass. These I
found to be slightlv malleable and magnetic, while they suf-
fered no sensible alteration before the blowpipe; — properties
that at once excited my curiosity, and led to my requesting Dr.
Duff to purchase the specimen for me. Sotnetime elapsed be-
fore he was able to effect the object, chiefly owing to the removal
of the original proprietor to a distance firom Butherfoirdc In



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260 C. U. Shepard on a Meteoric Iron? from iV. CaroUna.

November, 1858, however, he sent the spedmen to me by the
hand of Bev. Mr. Bowman ; and a month after addressed me



Online LibraryIrving Browne Isaac Grant ThompsonThe American journal of science and arts → online text (page 86 of 111)