On account of the enormous cost of coal, various substitutes are in use. On the plateau there is practically no wood. For heating, foreigners generally employ oil stoves, the natives nothing at all, though the mercury may range from 40° to 50° in the house on a winter’s day. In La Paz for cooking purposes a substance called _taquia_ is employed. It looks like pecan nuts, but is the dung of llamas, which is collected by Indians on the plateau or elsewhere. It sells generally at about $4 a ton, but has lately risen to $7. It is the principal fuel used at the mines of Corocoro. In some places as at Potosí, _yareta_ is used, a vegetable or shrub which grows in a dense mass to a height of several feet with a greater diameter. The green mass has a woody fibre, is highly resinous, and burns like peat, giving a good amount of heat. It grows at altitudes between 13,000 and 16,000 feet. Another woody shrub, a species of broom called _tola_, is used, with another, _quenua_, which like charcoal gives much heat with little ash. Extensive peat beds exist near La Paz, estimated to yield 30,000,000 tons of briquettes with a fuel value about half that of coal. The discovery and wide exploitation of coal and petroleum would be an immense boon both to industry and to the householders. =Petroleum= is now believed to exist in large quantities, sufficient to solve the fuel problem. The best known fields are in the southeast where seepages occur and a belt is indicated extending northwest and southeast 150 miles from the Argentine border. Concessions covering millions of acres have been granted to American companies. The zone traverses the Provinces of Santa Cruz, Chuquisaca, and Tarija. Geological investigations indicate that a petroleum belt or basin exists along the foothills of the east side of the East Cordillera. There are indications in the Beni district a considerable distance north of La Paz, and beyond the Madidi in Colonias. A probable thickness of over-lying strata in southeast Bolivia is 160-660 feet. If so development costs will be diminished. The great difficulty is the inaccessibility of the locations. On this account few wells have yet been sunk. To pipe the oil up to the plateau would be an expensive, some say an impracticable, proposition. At present approached only by cart roads or caminos, the fields will be rendered more accessible by the railways planned from Puerto Suarez or Pacheco and from Argentina to Santa Cruz. The oils vary in quality, some having an asphalt base with 4 per cent of gasoline, up to .81 specific gravity with 40 per cent of gasoline. The heavier is in the lower sands. Along the eastern base of the Andes the petroleum is of high grade. Samples of oil from Espejos Spring, 12 leagues from Santa Cruz, indicate the quality expected north to the Madre de Dios. This has 78 per cent kerosene, 17 lubricating oil, and 4 per cent coke. From indications it is believed that gushers would come by boring to proper depth. It is said