Reconnaissance of superficial phosphate deposit near Minas, Uruguay

The phosphate deposit in Uruguay described here is of interest primarily because it is believed to be a superficial deposit that resulted from the action of guano on volcanic rock. Even though some of the rock contains as much as 30 per cent P206, it is unavailable as a source of fertilizer because the phosphate is combined with aluminum and iron as variscite and strengite, and possibly other equally insoluble minerals. © 1953 Society of Economic Geologists, Inc.