CHANGES IN KNOWN GEOGRAPHICAL DISTRIBUTION IN THE FUTURE
As with most metalliferous ores that have been formed later than the deposition or solidification of their inclosing rocks, the ores of quicksilver are most likely to be found in regions of eruptive activity and complex geologic structure, especially in regions of comparatively late volcanic disturbance. It follows that new deposits are most likely to be discovered within the areas of Tertiary or post-Tertiary volcanic activity, as in the Cordilleran belts of North and South America, the eastern coast of Asia, certain parts of Oceania, and the shores of the Mediterranean. Alaska, Mexico, and the western part of South America seem to offer the greatest possibilities of future productivity, but there is little probability of any important changes in the sources of quicksilver taking place in the near future. The value of a quicksilver deposit can be ascertained as a rule only by mining exploration, and in very few quicksilver mines can any safe estimate be made of “undeveloped” ore. The known facts afford no secure basis for predicting that in the near future some now unimportant district will, within the next ten years, wrest the supremacy in production from Spain, or compete with Austria, Italy, California, or Texas. As regards the principal known sources, it appears that the high-water mark of productivity in California has long been passed, although the mines are still capable of increasing their present production under sufficient stimulus. The Italian output has been increasing of late years, but whether this represents the discovery of new ore bodies or indicates a longer life for the Monte Amiata district is uncertain. A permanent improvement in the political conditions in Mexico, with a continuance of the present, or higher, prices, would probably lead to a notable increase in yield from that country. There is some probability also that Peru may again become an important source of quicksilver.