perviance, several names have been suggested to me, the best of which is diviance, from dis, via. Here the prefix dis must have the effect which it has in such words as discomfort or discourtesy. It denotes a lack of the quality without implying a total absence of it. The word diviability would then represent the reciprocal of perviability.

Issued Jan. 21, 1895.

variety, is occasionally intermixed, and less frequently pyrite. The lignite is brown in color, shows an eminent wood structure, and dries out on prolonged exposure, becoming heavily checked and very tender.

The coarse sand and gravel of recent age that overlays the sandstone is cross-bedded (showing that it is a channel deposit of the river), and contains abundant fragments of drift-wood that is more or less lignitic. None of these lignitic fragments in the sand contain any blende, which shows that the zinc was introduced before they were deposited.

This occurrence of blende in this basal coal-measure sandstone is very interesting from its bearing on the problem of the origin of our Missouri zinc deposits. For though only found in specimen quantities, it shows that during or since the coal-measure epoch, this coarse-grained, porous sandstone has been permeated with solutions carrying zinc-sulphate, from which by the reducing action of the lignite, the soluble zincsulphate has been reduced to the insoluble zinc-sulphide or blende, and precipitated in the interstices and cracks of the shrinking lignite. The blende is only found in the lignite, so that large amounts of zinc may have been present in the sandstone, but was only retained where locally converted by the lignite into the insoluble blende.

The nearest known occurrence of zinc is in the quarries in the underlying St. Louis limestone that are worked five to ten miles south, where small disseminated grains of crystalline blende occur occasionally in the geode-bearing magnesian limestone beds; the latter are sufficiently porous for the feeble infiltration of solutions, and organic matter in the limestone seems to have precipitated slight amounts of zinc. Numerous other instances of occasional disseminated grains or nodules of zinc have been observed in the neighboring limestones, and unsuccessful attempts at zinc-mining have been made near Troy, in Lincoln County, 45 miles northwest, and at Hannibal, 90 miles, at the base of the Sub-Carboniferous. The nearest producing zinc mines are 50 miles south, at the Vallé Diggings, in St. Francois County, where the zinc occurs in gash-veins, associated with galena in magnesianlimestone of Lower Silurian or Cambrian age; while the great

zinc region of Southwest Missouri, where the zinc occurs so extensively in irregular bodies in broken chert and limestone of Sub-Carboniferous age, is 250 miles southwest.

Dr. W. P. Jenney* thinks that the zinc occurrences of the Mississippi Valley are all of the same age, and that the source of the zinc was from below. While the former idea of contemporaneous age may be possible, the occurrence of the disseminated grains in the St. Louis limestone and in the seams of the lignite in the Baden sandstone, decidedly show that in at least these two cases the zinc was derived from lateral secretion. The Baden sandstone, which is the equivalent of the "Ferruginous" or at the base of the Coal Measures, also shows that the zinc was introduced at least as late as the Coal Measure period, but not so rccent as the Quaternary; the lack of any formations between these horizons prevents any closer determination of this question.

The writer is indebted to Mr. J. Gordon Reel, C. E., the engineer in charge of the work, for an excellent suite of the blende specimens.

"Lead and Zinc Deposits of the Mississippi Valley." W. P. Jenney, E. M. Transactions American Inst. Mining Engineers. Vol. 22.

Issued February 21st, 1895.

RECENT ADDITIONS TO THE MINERALOGY OF

MISSOURI.

H. A. WHEELER, E. M.

(Read by title at Academy meeting, March 17th, 1890.)

A contribution to our Missouri mineralogy was made in Vol. 4, p. 440, of the "Transactions of the St. Louis Academy of Sciences" by Mr. A. V. Leonhard who, in a paper entitled “Notes on the Mineralogy of Missouri," describes 70 species and 5 varieties of minerals that are found in the State of Missouri. Later collectors have since added 48 more species and 11 additional varieties to our local mineralogy, which are herewith given (1894) as a supplement to Mr. Leonhard's list (1884).

GOLD.

Placer Gold. Occasional occurrences, in small amounts, in the Glacial Drift in the Northern and Western parts of the State; by Norwood and Broadhead.

SILVER.

Argentiferous Galena, at the Einstein mine, in Madison County, in a fissure-vein in archean granite; it assays 100 to 300 ounces per ton, but is not abundant.

MERCURY.

Native Mercury. In the Loess or surface clay at Cheltenham station, St. Louis, in very small amounts, by J. P. Gazzam, E. M.; is probably of artificial origin.

TIN.

Cassiterite was reported as occurring as disseminated grains in greenstone near Frederickstown, in Madison County; a large company was formed in 1871 to work it, but it proved to be a case of "salting."

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COPPER.

Chrysocolla, at the Cornwall Copper Mines, in St. Genevieve County, as a thin incrustation with other oxidized products in the chalcopyrite-bearing limestone, by H. A. Wheeler ;

uncommon.

LEAD.

Leadhillite. In small green crystals and clusters, of exceptional beauty, from a lead mine near Granby, Newton County. See American Journal of Science, Sept., 1894. Mimetite, at Seneca, in Newton County, as a thin crystalline coating on galenite, by Dr. W. P. Jenney; rare. Artificial Silicate of Lead. Beautiful hexagonal prisms of lead-silicate, resembling Pyromorphite, of an opaque brown to transparent ruby-red color, and with a resinous fracture, from the hearth of a lead roasting-furnace at Bonne Terre, by J. T. Monell, E. M. See American Journ. Science, Aug., 1885, and Sept., 1886.

ZINC.

Goslarite, at Joplin, Jasper County, as a white, stalactitic incrustation in the blende mines; first found very sparingly by Broadhead, and later quite frequently in the drainage of the mines, by Dr. W. P. Jenney. Ferro-Goslarite, at Webb City, Jasper County, as a brown stalactitic incrustation in the old-workings of the zincmines, by H. A. Wheeler; rare. See American Journ. Science, Mch. 1891 (Vol. 41).

Amorphous Sphalerite, as an amorphous, white, pulveralent mass or "natural-paint" in a zinc mine at Joplin, Jasper County, by J. D. Robertson. Only a single pocket of a few tons was found, and was evidently the result of recent oxidation of the blende and subsequent chemical precipitation.

TITANIUM.

Rutile, in Southeastern Mo., in the granites, as an accessory mineral of microscopic size, by Dr. E. Haworth; rare?

NICKEL.

Siegenite. A new occurrence of this nickeliferous Linneaite has just been found (Nov., 1894) at the Donnelly Lead