In its general surface features South America resembles North America--that is, a central plain is bordered by low ranges on the east and by a high mountain system on the west. In the southern part, midsummer is in January and midwinter in July. The mineral-producing states are traversed by the ranges of the Andes and all of them except Chile are situated on both slopes of the mountains. =Colombia.=--This republic borders both the Caribbean Sea and the Pacific Ocean. One port excepted, however, most of its commerce is confined to the shores of the Caribbean Sea. The lowlands east of the Andes are admirably adapted for grazing, and such cattle products as hides, horns, and tallow are articles of export. This region, however, even with the present facilities for transportation, produces only a small fraction of the products possible. The intermontane valleys between the Andean ranges have the climate of the temperate zone; wheat and sheep are produced. The chief industrial development, however, is confined to the lands near the Caribbean coast. Coffee, cacao, and tobacco are grown for export, the business of cultivation being largely controlled by Americans and Europeans. Rubber, copaiba, tolu, and vegetable ivory[59] are gathered by Indians from the forests. [Illustration: A PASS IN THE ANDES] The montane region has long been famous for its mines of gold and silver. The salt mines near Bogota are a government monopoly and yield a considerable revenue. Near the same city are the famous Muzo emerald mines. The rivers are the chief channels of internal trade. During the rainy season steamboats ascend the Orinoco to Cabugaro, about two hundred miles from Bogota. About fifty steamboats are in commission on the Magdalena and its tributary, the Cauca. Mule trains traversing wretched trails require from one to two weeks to transport the goods from the river landings to the chief centres of population. Improvements now under way in clearing and canalizing these rivers will add about five hundred miles of additional water-way. The railways consist of short lines mainly used as portages around obstructions of the rivers. An unstable government and an onerous system of export taxes hamper trade. Coffee, a leading product, goes mainly to Europe. Cattle products, and balsam of tolu are purchased mainly in the United States. Great Britain purchases the gold and silver ores. The chief imports--textiles, flour, and petroleum--are purchased in the United States. _Bogota_ and _Medellin_ are the largest cities. The isolation of the region in which they are situated shapes the indifferent foreign policy of the government. _Barranquilla_, _Sabanilla_, and _Cartagena_ are the chief ports.