GEOLOGY. The mountain regions here have long been the seat of great volcanic activity. The chief formations in the central range are granite. gneiss, basalt, and eruptive rocks, while in the eastern range Cretaceous formations pre dominate. The geological structure of the West ern Cordillera has not yet been fully investigat ed. The entire portion east of the Cordilleras is occupied by the Ilanos—vast treeless plains having an altitude of from 1000 to 1500 feet. and well adapted for pasturing. The isthmus section is partly hilly and partly low and swampy.
31fivEn.u. RESOURCES. Colombia is very rich in minerals, especially in precious metals. Gold is found mostly in alluvial deposits and in the streams. During the Spanish regime the pro ceeds from the gold-mines constituted the chief revenue; but the extracting was carried on by most primitive means. Modern methods were introduced only during the last quarter of the nineteenth century, though the principal mines have long been operated by English companies. The chief centre of gold-mining is Antioqufa, which yields about $200,000 per annum. The leading silver-mines are in Tolima and Cauca. The annual silver output of the country amounts to nearly $4.000,000. The other mineral re sources—iron, copper, platinum, lead, and salt —are little developed. Emeralds are mined chiefly in the Department of Santander. the mines of Muzo being the most noteworthy. Salt mining, a Government monopoly, is carried on chiefly around Zipaquirfi and Nemociin, where salt is found both in rock form and in springs.
Coal exists in the Eastern Cordillera and in many other parts, but is as yet scarcely touched.
AGRICTI:El RE. The principal industry of Colombia is agriculture. is greatly favored by the soil and climate, but is carried on by primitive methods. Cultivation is confined mainly to the elevated plateau of the western part. These seetions are best adapted to settle ment by European immigrants, on account of the salubrious climate. In the hot districts the chief plants are coffee, tobacco, sugar, cacao, etc. Tobacco, and especially coffee, are largely ex ported. In the less torrid regions the agriculture is more European in character, wheat. corn, and barley being leading crops. The banana-tree is found all over the Republic. and the fruit is exported in large quantities, mostly to the United States. The absence of adequate trans portation facilities and the sparseness of popu lation are such hindrances to agriculture that the total yield of the food crops is not sufficient to satisfy the home demand. and the deficiency has to be made up by imports. The rubber-tree and the copaiba-tree grow wild and are tapped but not cultivated. The uplands are the home of the toll, well known for its balsam. Cattle raising is conducted on a considerable scale, especially on the Banos. In 1901 the number of cattle in the Republic was estimated at 3,450,000. Both cattle and hides form prominent items of export.