=Copper.= Of late the copper deposits in Peru and Chile have received more attention than those of Bolivia, but this country also has extensive formations from Lipez at the south where white copper is found, along the East Cordillera, past Potosí and Oruro to Corocoro in the West, ending in the Nudo of Apolobamba. Veins occur in all the buttresses of the Andes. Copper is found chiefly in its native state, the deposits of Corocoro being especially famous. The copper here occurs in powder, plates, or nodules, in beds of reddish sandstone. One veta, or mineralized bed, is 1000 yards deep, extending several miles; another, a branch formation above this surrounds it on the southwest and east, occupying a great part of the Desaguadero Valley. Both formations are arseniates. One branch 2000 yards thick extends 6 miles; in another direction a branch runs 35 miles from Corocoro to Chacarilla, then branching south and east. Copper generally occurs in small irregular grains with from 70 to 92 per cent copper. The native copper, the great wealth of the mines, here ranges from microscopic grains to plates and arborescent forms called charquis. At La Charcarilla large plates are found 3¹⁄₂ inches thick. Ores with 15-20 per cent copper are usually neglected. As there are no good kilns, barilla is exported 80 per cent pure, a quintal, 220 pounds, costing $3-4 for production. Except from Corocoro the present output is insignificant. For a time these mines were abandoned owing to the low price of copper and the difficulty of transport. It was formerly necessary to send the barilla by carts, mules, or llamas to the port of Arica, or else to the Desaguadero River, to be carried in boats to Lake Titicaca and Puno, thence by rail to Mollendo. With the great increase in the price of copper and the opening of the Arica-La Paz Railway with a 5 mile branch to Corocoro, these difficulties were removed and active work progressed with a broad field for enlargement. Copper formation here is said to resemble greatly those in Northern Michigan, such as the Copper Range, and the Calumet and Hecla. In 1917 over 82,000,000 pounds were exported, worth above $4,000,000. =Lead= is found in the region of La Quiaca and some is exported by way of Argentina. Galena, an ore of lead and silver, is widespread. =Bismuth.= Of less used minerals bismuth may be mentioned, in the production of which Bolivia leads the world and controls the supply. At present, chiefly used as a drug on account of its high price, it might be more largely employed in alloys. Bismuth ore, as carbonates, oxides, and arsenical sulphates, is so abundant in many parts of Bolivia that if bismuth sold at 20 cents a pound a fair profit would be realized. With the price for years $3500 a ton, it would seem a profitable business to engage in. Over one million pounds were exported in 1918 worth one and a half million dollars.