showing very distinctly one rhombohedron, scalenohedron and basal plan; it is coating tetradymite and evidently a pseudomorph after it. I have seen other specimens from the same locality, but of inferior value and beauty.

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

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

c. In the upper portion of the ore bed in the metamorphic slates at Springfield, Carroll county, Md., which, near the surface, consists of magnetite and at a greater depth of chalcopyrite and other ores, sometimes films of native gold have been observed coating the cleavage planes of magnetite. On close examination it can be noticed that below the film of gold the magnetite is oxydized into hydrated sesquioxyd of iron.

d. A very striking occurrence of native gold is, that where it is associated with 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 the 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 the result of the reduction of iron-salts and bear in mind that protosalts of iron reduce gold instantaneously, 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 Winter's vein, Calaveras county, California, show beautifully that, wherever there is a crystal of pyrites, small crystals of gold are attached to it, demonstrating, that the sulphate of iron precipitated the gold, previous to its own reduction into pyrites.

All these facts 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.

If another proof was wanted to show the fallacy of this idea, it would be the fact 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, 1859.

ART. XXXI.-Notice of a Memoir by M. Jules Marcou, entitled "Dyas and Trias or the New Red Sandstone in Europe, North America and India."* (In a letter from Sir RODERICK I. MURCHISON to the Editors.)

Gentlemen

In the early part of last winter I read with surprise the following paragraph in a published letter by M. Jules Marcou on American Geology. "I 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 Murchison has put into his Permian a part if not the whole of the Trias, and I am almost certain that if geologists accept the Russian 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 Russia, I called his notice to another expression in his own letter on American geology in which he says: "not having visited Kansas or Nebraska I have no decided opinion respecting the geology of those countries; for I profess the doctrine 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 Russia, before he passed so severe a judgment on the researches of M. de Verneuil, Count Keyserling and myself. The replies sent to me by that gentleman, 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.

After a study of the original work of my friends and self, M. Marcou has at length produced his results in the. Bibliothèque Universelle de Genève under the title of which a translation is given at the head of this letter.

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

All such persons know, and particularly those who have read the new edition of my work on Siluria, that the absolute distinction between the fossils of the Permian group or Dyas of M. Marcou and those of the Trias is much more sharply defined

* Bibliothèque Universelle de Genève, Mai et Juin, 1859.

than ever, and yet he reverts to the former and obsolete state of the science and merges these two most markedly separated deposits in one natural group. The author applies his new word Dyas' to the rocks in question because the two deposits only of Rothe-liegende and Zechstein chiefly prevail in certain tracts; but geologists who have gone through all the proofs I have adduced 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 classification, ought to operate in my favor. It is quite true that in most parts of the vast region of Russia (larger than France) occupied by the rocks to which I assigned the name of Permian, there 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 I established by visits to all the classical districts of Germany before the publication of the work on Russia and by comparing them with those of Russia is, that whether the pebble-beds and sandstones underlie the Zechstein as in Germany or are intermixed with and chiefly overlie all the limestone as in Russia, the plants of the two regions have been pronounced to be identical. These plants are related generically to the Carboniferous forms, whilst on the authority of Göppert they are pronounced to be entirely distinct from those of the Trias.

In short, the whole geological series does not offer a more complete discordance of type between any two conterminous groups than that which exists between the fossils of the PerInian and those of the Trias, whether we refer to their respectively imbedded reptiles, fishes and shells, or to their plants; the one set marking the close of Paleozoic, the others the commencement 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 resumé," &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 paleozoic division of life, the inhabitants of the Permian era, and by op

SECOND SERIES, VOL. XXVIII, No. 83.-SEPT., 1859.

posing the views of an author who considers such fossils to be the remains of "precocious beings"-the 'precursors' or 'advanced guard' of the secondary or Mesozoic populations!"

I remain gentlemen, your very obedient servant,

RODERICK I. MURCHISON.

Geological Survey Office, London, July 25th, 1859.

เ

P. S.-Informing his readers that my eminent friend M. d'Omalius d'Halloy had named the same rocks Penéen ('poor') which I afterwards termed Permian, M, Marcou should recollect, that when I wrote my first letter on the subject to Dr. Fischer at Moscow in 1842, I was far distant from any works of reference. When, however, I consulted the Eléments de Géologie' of d'Omalius, published in 1831, I found that although that sound geologist had widely separated his 'Penéen' 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 geographical name taken from a country where fossils abounded, to a term which implied poverty of fossils. In fact, M. d'Omalius tells us (p. 276) that his name Penéen was intended as a French translation of Roht-todt-liegende, the examples of which rock, best known to the Nestor of Belgian geologists, near Malmedy, are indeed quite sterile, as I 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. I. Murchison's letter.-EDS.

"To sum up, I am led to regard the New Red Sandstone comprising the Dyas and Trias as a great geologic period, equal in time and space to the Palæozoic epoch, or the Graywackés (Silurian and Devonian), the Carboniferous (the Mountain Limestone and Coal Measures), the Mesozoic (Jurassic and Cretaceous), the Tertiary (Eocene, Miocene and Pliocene), and the recent deposits (Quaternary and later). I also restrict the limits ordinarily ascribed to the Paleozoic and the Mesozoic, and give them proportions more in harmony with those of the Tertiary and recent epoch-to the end that we may have a well balanced and natural classification.

"In the New Red' as well as in all other great epochs, we remark that the lower beds (the Roth-liegende) contain Carboniferous forms of life-a kind of rear guard' of the populations 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

similar to their predecessors, are endowed nevertheless with other forms, and of necessity therefore with other habits, associations, and aspects-exactly like the centenary in our human societies. On the other hand, the upper beds of the New Red, such as the 'Halstatter Kalk,' the 'Raibler Schichten,' the 'Bonebed,' or the Keuper contain forms indicating the approach of another geologic period of secondary beds (Jurassic and Cretaceous), 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 great events are on the point of fulfillment. Or, better still, they may be com. pared to plants which, forced in hot-houses, flourish in the winter, in place of awaiting the spring and whose pale-tinted flowers, and etiolated or disproportioned forms, appear as if they knew that they were before their time, and as if it was only a species of tentative experiment, which they were performing and so they hastened to disappear to make room for the vigorous and abundant flora of the warm season."-Bibliothèque Universelle (de Genève), Juin 20, 1859, pp. 145, 146.

[Obs. It will be interesting for the reader to turn 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 our author's assumed Jurassic beds. See p. 298.]

ART. XXXII.—Examination of a supposed Meteoric Iron, found near Rutherfordton, North Carolina; by CHARLES UPHAM SHEPARD.

FOR my first knowledge of this Iron, I am indebted to Dr. Thomas S. Duffy of Rutherfordton, who in the winter of 1857 casually mentioned to me at Charleston, that he had been shown. a very remarkable specimen of an ore found in his vicinity, of the character of which no one had been able to pronounce a satisfactory judgment. From his description of its lustre and color, and of certain striæ 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 slightly 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. Sometime elapsed before he was able to effect the object, chiefly owing to the removal of the original proprietor to a distance from Rutherford. In