Another curious fact in the mineralogy of California is the occurrence of some mineral species which are common as ores in other mining countries, and which in California, or at least in the mining region of the Sierra Nevada, are disseminated through a great number of localities, but nowhere exist in workable quantity. Galena and blende may be particularly referred to as occurring in this way. There is hardly a gold-bearing vein in the Sierra which has not some galena and blende in fine particles in the veinstone; but not a locality is known where the quantity of either of these ores is anything like sufficient to justify mining, even were the other conditions as favorable as in the Eastern States or in Europe. Galena occurs in considerable quantity in the extreme south-eastern portion of the State, or just over the borders, in Arizona and Nevada; but no considerable deposit of zinc blende has yet been made known anywhere in the Pacific States or Territories; nor is any other ore of zinc known to occur in workable quantity on this coast.
The mineral region with which ours most nearly agrees, in the character of its ores and mineral substances, is that of the South American Andes, especially of Chile. In Mr. David Forbes’ recent catalogue of the Chilean minerals, there are about two hundred species enumerated, of which about sixty have hitherto been discovered in California and the other Pacific States and Territories. The Chilean mineral list, like that of California, is remarkable for the absence of many of the almost universally distributed silicates mentioned above as wanting in the Pacific States, namely: beryl, topaz, zircon, Wollastonite, Allanite, iolite, staurotide, kyanite, spodumene, spinel and datholite. Many other silicates, abundantly distributed throughout other portions of the world, might be mentioned as entirely wanting along the whole Pacific Coast. Several of the more common zeolites are found in the Chilean list, which are wanting in California; while several others are equally wanting in both countries. Among the common zeolites found in Chile which have not yet been discovered in California are Prehnite, stilbite, Laumontite and scolecite; while analcime, harmotome, Thomsonite, natrolite and Heulandite are wanting there as well as here.
It is evident, from a comparison of the mineral lists of the States situated along the Pacific Coast of North and South America, that there has been a most remarkable resemblance in the conditions which have influenced the formation and segregation of the accidental minerals now found accompanying the stratified and eruptive masses throughout the whole vast extent of the regions in question. This is another of the facts which go to show the unity of the Cordilleras of North and South America as a geological result.
Mr. Bolander stated that the absence of many mineral species from this coast found its parallel in a similar absence of many botanical groups.
Dr. Cooper did not think there was any poverty with respect to animal species on this coast, and suggested that the absence of certain groups of plants might be due to the absence of certain appropriate mineral constituents from the soil.
Dr. Behr thought that the Californian lepidoptera more nearly conformed to European and Mexican types than to those of the Eastern States.
Regular Meeting, November 18th, 1867.
President in the chair.