High, rich in hematite iron ore; valuable limestone deposits are found some 30 m.
Institutions possessing a special character are the monti frumentarii, public grain deposits, founded for the purpose of supplying peasant proprietors with seed corn, debts being paid in kind with interest after harvest.
The superiority which is claimed for Burton ales is attributed to the use of well-water impregnated with sulphate of lime derived from the gypseous deposits of the district.
Deposits of copper, tin, iron and tungsten have been discovered, and a variety of other mineral products (graphite, mica, spodumene, coal, petroleum, &c.).
The marine facies of the later Tertiaries is confined to the neighbourhood of the coast, and was probably formed after the elevation of the Andes; but inland, freshwater deposits of this period are met with, especially in Patagonia.