Tungstate of manganese.-With tungstate of lime, in the Mammoth mining district, Nevada. (C. T. Jackson, Proc. Cal. Acad., iii, 199.) Variegated copper ore, ("Horseflesh ore.")-Sigel lode, in Plumas county. Principal public and private mineralogical and geological collections in California, known to the author. I.-PUBLIC COLLECTIONS. STATE GEOLOGICAL COLLECTION-Sacramento and San Francisco; not arranged, and in part destroyed by fire in eighteen hundred and sixty-five, at the Pacific warehouse. STATE AGRICULTURAL SOCIETY'S-At Sacramento; partly in cases, but not classified or arranged. SAN JOAQUIN AGRICULTURAL SOCIETY-At Stockton; collected chiefly by Dr. Holden; not large, nor well arranged. CALIFORNIA ACADEMY OF NATURAL SCIENCES-At San Francisco; not arranged; in boxes, and stored, awaiting a suitable room or building for their display. This collection was made in great part by and through the exertions of Dr. J. G Trask, and has many valuable specimens taken from our mines soon after their discovery. COLLEGE OF CALIFORNIA-At Oakland. A collection of minerals and fossils of California; partly arranged. SANTA CLARA COLLEGE. (No particulars known.) ODD FELLOWS' LIBRARY ASSOCIATION-At San Francisco. A valuable miscellaneous collection of minerals, ores, fossils, and curiosities, chiefly the donation of the members of the Order; arranged in cases, at the Hall. The Order is indebted, chiefly, for this valuable addition to their rooms, to the zeal and enthusiasm of their president, S. H. Parker, esq. OCCIDENTAL HOTEL-Lewis Leland, San Francisco. A collection containing many very choice and valuable specimens of ores and precious metals of the Pacific coast. II. PRIVATE COLLECTIONS. W. P. BLAKE-At San Francisco and Oakland. A collection of minerals, ores, geological specimens, and fossils, from California, Nevada, Arizona, Idaho, Mexico, the eastern States, Japan, and China, with some European minerals. About sixty boxes of this collection were destroyed in the Pacific warehouse, by fire, in eighteen hundred and sixty-five. A portion, stored at the college and elsewhere, was uninjured. It is now partly in boxes, and partly in cases, in San Francisco, and at the College of California, Oakland There are probably five thousand to six thousand specimens, a great part of them selected by the owner at the localities. It contains a valuable and extensive suit of crystalline gold. Dr. J. M. FREY-Sacramento. A large and valuable miscellaneous collection of Pacific coast minerals, including a fine suit of gold in crystals. Arranged in part, in cases, in Sacramento Dr. JOHN HEWSTON, Jr.-San Francisco. Miscellaneous collection. Dr. JONES-Murphy's, Calaveras county. A miscellaneous collection, chiefly local. A. P. MOLITOR-San Francisco. Miscellaneous collection. R. L. OGDEN-San Francisco. A miscellaneous collection of copper and gold ores. A large collection made by this gentleman up to eighteen hundred and sixty-one, was purchased by W. P. Blake, in eighteen hundred and sixty-one. AUGUSTE RÉMOND-San Francisco (No particulars known.) Dr. SNELL-Sonora, Tuolumne county. A rich and valuable collection of fossils and aboriginal relics from the auriferous gravel under Table mountain, and of minerals and ores from that region. This is the richest collection of relics of the mastodon and the mammoth in California. T. J. SPEAR-San Francisco; formerly at Georgetown, in eighteen hundred and sixty-two and three. A small miscellaneous collection, which included an ammonite, from the gold slates of the American river; valuable to science as one of the evidences of the secondary age of the gold-bearing rocks of California. Dr. STOUT-San Francisco. A miscellaneous collection of Eastern and European specimens, arranged in cases. C. W. SMITH-Grass valley, Nevada county. An interesting collection, arranged in cases, and containing some choice specimens from the mines of Grass valley. Dr. WHITE-Placerville, El Dorado county. A miscellaneous collection, containing many interesting specimens from that region, and some foreign minerals, by exchange. W. R. WATERS-Sacramento. ores, arranged in case. Miscellaneous collection of minerals and Notes on the geographical distribution and geology of the precious metals and valuable minerals on the Pacific slope of the United States. If we attempt to delineate by colors upon a map the geographical distribution of the gold, silver, copper, and quicksilver localities of the Pacific slope, we obtain a series of nearly parallel belts or zones, following the general course or trend of the mountain chains and of the coast. So, also, if we enter the Golden Gate and travel eastward across the country to the Rocky mountains, we pass successively through zones or belts of country characterized mineralogically by different metals and minerals. In the Coast mountains, for example, quicksilver is the chief, and the highly characteristic economical mineral. The localities of its ore are strung along the mountains through the counties north and south of the Golden Gate. We have also petroleum, sulphur, and calcareous springs, nearly coincident in their distribution. Passing from this grouping of minerals eastward over the coal beds of Mount Diablo, and crossing the great interior valley of California, (probably underlaid by lignite,) we rise upon the slope of the Sierra Nevada, and reach the copper-produc ng rocks. These form a well marked zone, which has been traced almost uninterruptedly from Mariposa to Oregon, following the lower hills of the Sierra Nevada. East of the copper belt, (and in the central counties, over a chain of hills known as "Bear mountains,") we find the great gold-bearing zone, characterized by lines of quartz ledges, following the mountains in their general northwesterly and southeasterly course. This gold belt is composite in its character-the veins traversing either slates, limestones, sandstones, or granite. Crossing the snow-covered crest of the Sierra, where in some parts iron ores have been found, we leave the region of gold and enter that of silver, mingled with gold, extending up and down the interior eastern slope of the Sierra throughout California, into Arizona and Mexico on the south, and Idaho on the north. At the Reese River mountains, further east, towards Salt Lake, the gold is replaced by silver, associated with copper, antimony, and arsenic; and this grouping is in its turn replaced by the gold-bearing sulphurets of the Rocky mountains. This is the general distribution of the precious metals. There are, doubtless, local exceptions. It is evident that this distribution of the metals and minerals in zones has been determined by the nature of the rocky strata, and by their condition of metamorphism. It is worthy of note that the minerals of the coast ranges are chiefly the more volatile and soluble, such as cinnabar, sulphur, petroleum, and borax, distributed in rocks ranging from the tertiary to the cretaceous, inclusive. The longitudinal extension of the gold-bearing zone is yet undetermined. The metal has been traced through the whole length of California, through Oregon and Washington, into British Columbia, and beyond, along the Russian possessions, towards the Arctic sea. Southward, it is prolonged into Sonora and Mexico, and there is every reason to believe that its extension is coincident with the great mountain chain of North America in its course around the globe, into and through Asia. After years of laborious search for fossils by which the age of the goldbearing rocks might be determined, I had the pleasure, early in 1863, to obtain a specimen containing Ammonites from a locality on the American river, preserved in the cabinet of Mr. Spear. This fossil was of extreme importance, being indicative of the secondary age of the gold bearing slates, and was therefore photographed, and copies of it sent to the Smithsonian Institution at Washington, for description. It was subsequently noticed in the proceedings of the California Academy of Natural Sciences, September, 1864. The same year, when at Bear valley, Mariposa county, upon the chief goldbearing rocks of California, I identified a group of secondary fossils from the slates contiguous to the Pine Tree vein, and noticed them at a meeting of the California Academy, October 3, 1864, announcing the jurassic or cretaceous age of these slates. The best characterized fossil was a Plagiostoma, (or Lima,) to which I provisionally attached the name Erringtoni.* The attention of the geological survey having been directed to this locality by my announcement and exhibition of the fossils in San Francisco and at the academy, Mr. Gabb, the palæontologist of the survey, visited the locality and obtained specimens. These fossils were of such interest and importance to science, and to the geological description of the State, that an extra plate was engraved for them and published in the appendix to the volume on the geology, recently issued.† Fossils of the secondary age from Genesee valley, in the northern part of the State, were common in collections in 1864, and are described by the State Geological Survey, volume one, "Palæontology." It appears also, from the same source, that Mr. King, a gentleman connected with the survey, had obtained belemites from the Mariposa rocks in 1864, but no figures or description are given. We may thus regard the secondary age of a part, at least, of the gold-bearing rocks of the Sierra Nevada as established, a result of no small importance practically, for it destroys the dogma, which has been very generally accepted, that the Silurian or Paleozoic rocks are the repositories of the gold of the globe. We may now look for gold in regions where before it was generally presumed to be absent, because the formations were not Silurian or Paleozoic. The Silurian age of the gold rocks of California has not always been assumed. It has been repeatedly questioned. In the preface to the writer's "Report of a Geological Reconnoissance in California," it is stated that a considerable part of the gold-bearing slates of California are probably carboniferous. The absence of all evidence of Silurian fossils west of the Rocky mountains is also distinctly noted. (p. 276.) The opinion of the comparatively modern age of the gold *In honor of Miss Errington, a lady residing on the estate, who drew my attention to some impressions on the slates which she had picked up on the English trail, which proved to be fossils. t I regret to observe that in this publication, as well as in Mr. Gabb's notice of the fossils, no mention is made of my previous aunouncement, and that my part in the discovery and publication of the secondary age of the Mariposa gold rocks is studiously and wholly ignored. rocks has been steadily gaining strength and support for years past, and has been the subject of discussion in the daily journals. The prevalence of gold in the Coast mountains, in or in close proximity to rocks of tertiary age, leads us to question whether it may not occur in the rocks of this late period also. The fact, recently ascertained, that gold is very generrally associated with cinnabar, makes it more than probable that the metal has been deposited iu formations as recent even as the Miocene, (or middle tertiary,) for, according to the best evidence we now have, this is the age of a part, at least, of the quicksilver-bearing rocks. Such a result need not surprise us, although so far in opposition to generally existing views of the geological association of gold. The geological age of the rocks has manifestly nothing to do with the deposition of gold; it is only necessary that the rocks should have a favorable mineral composition and a suitable degree of metamorphism. On this general view, we may be prepared to find gold in rocks of any geological period, from the tertiary to the Laurentian or Huronian rocks, inclusive. The lithology of the chief gold-bearing zone or belt of rocks of California is interesting. The chief or "mother vein" extends through several counties, with occasional breaks or interruptions; and throughout its course preserves its distinguishing characters. It follows also the same geological horizon or zone, keeping between well-marked geological and geographical boundaries, so that a description of the strata adjoining it at one place will serve to give a general view of them throughout. A cross-section in considerable detail was made on the Mariposa estate in eighteen hundred and sixty-four. This estate includes the southern end of the Great Vein," there known as the Pine Tree." It also includes several veins lying west of the line of the Pine Tree, of which the most important is the "Princeton," noted for its richness and large production of gold. This group of veins follows a long valley between two high ridges— Bear Mountain on the west, and Mount Bullion on the east. Those ridges are formed of hard rocks; the rocks of the valley are argillaceous and sandy slates and sandstones. The stratification of these slates is remarkably regular and distinct; their thin outcrops standing sharply out at intervals in long lines in the ravines and on the hillsides, mark their trend, and show that they are nearly vertical, or have a slight inclination northeast or easterly. The general direction of the outcrops and of the valley is northwest and southeast; but there are several local variations. These slates are generally light colored or drab at the surface; but in depth they are black, like roofing slate, and break up into rhomboids. This is particularly well shown at the Princeton vein. There are numerous intercalations of sandy layers passing into sandstones-sometimes into coarse grits, and even pebbly beds, and beds of slaty conglomerate. The softer and most finely laminated portion of the group is generally found near the medial line of the valley, and is the point at which the Princeton vein occurs. It is near this part of the series, at the northern end of the estate, that the jurassic fossils occur. The following is an approximate geological section of the estate, at right angles to the course of the rocks, and nearly over the Princeton vein. It is a composite section, being made up of three distinct portions where the observations had extended, but all near together, so as to present a fair view of the sequence of the formations. The whole embraces a distance of about four miles, according to the scale of the small published map of the estate. The southwestern end is taken along Bear creek, the middle portion across the Princeton vein, and the remainder on a line near Upper Agua Fria, northeasterly to Bullion ridge. The following is the sequence of formations from west to east: SECTION ACROSS THE MARIPOSAS. 1. Coarse, heavy conglomerates, metamorphosed-Bear mountains. 2. Compact crystalline slates; crystalline cleavage. 3. Conglomerate; slaty. 4. Argillaceous slates, regularly stratified; thick series. 5. Sandstone and sandy beds, (thin.) 6. Princeton gold vein; quartz three feet thick. 7. Argillaceous slates and quartz veins; the horizon of the jurassic fossils. 8. Magnesian rock and quartz veins. 9. Pine Tree, or "Mother Vein," or its extension. 10. Argillaceous slates. 11. Conglomerate; slaty. 12. Compact slates. 13 Greenstone, limited in extent; probably a metamorphosed sandstone. 14. Sandstones and sandy slates. 15. Serpentine and magnesian rocks-the northern extension of Buckeye ridge. 16. Compact slates, crystalline and much metamorphosed. 17. Conglomerates and sandstones, heavy and massive; the so-called " greenstone of Mount Bullion range. This is the general outline of the formations. Both of the bounding ranges of the valley are formed by the heavy metamorphic conglomerates, so much altered and changed as to be scarcely recognizable. They are generally supposed to be formed of greenstone, and in some places they do not give any evidence of their sedimentary origin; in others, the outlines of the pebbles and boulders are distinct. These boulders are remarkably large and heavy. From the general similarity of the rocks of these two ranges-Bear mountain on the west, and Bullion range on the east-together with the succession and character of the formations between, I am led to regard the whole series as a fold or plication, and the valley as either synclinal or anticlinal-probably the former.* Bear Mountain range is prolonged far to the north into Calaveras county, and there forms the separation between the valley of Copperopolis, traversed by the Reed or Union copper lode, and the gold quartz region of Angel's camp and Carson Hill. The whole belt of formations from Amador county, southeastward, through Calaveras, Tuolumne, and Mariposa counties, is an interesting field for a geologist to work up, to show not only the geographical extent of the rocks and the veins, but the structure or folding of the whole. The two lines of hard conglomerate forming the high ridges are distinct for nearly the whole distance. The serpentine rocks which accompany the gold formation are probably the result of local metamorphic action, for they often occur in lenticular or elipsoidal patches in the other rocks. So also the greenstone, in places, appears to be an altered portion of rocks, which at other points are distinctly sedimentary, and exhibit slaty stratification. *The above section of the gold formation of the estate, and the substance of the observations upon it, were given in a report to F. L. Olmsted, esq., in eighteen hundred and sixty-four. Inedited. |