a long period of repose suddenly became active again in 1920), and Iztaccihuatl the White Woman. 5,286 metres. Only these volcanoes are clad in everlasting snow. The present snowline lies itt about 4.100 metres Other well-known volcanoes are the Nevada de Toluca (Xinantecatl) 4.578 metres, and in the State of Jalisco, the Nevada de Colima (1,378 metres), with its side cone thrown up in 1869. All these volcanoes are formed of andesitic lava and ashes. A vilcano built up in historic times is the 1,700 feet high basaltic cone of Mt.Jorullo in the state of Michoacan, rising to a height of 1,820 metres above sea level. The Mesa Central ceases abrupily south of the volcanic zone and splits up into a ruused low mountainous district deeply carved by the Rio Balsas and its tributaries. The greatest range in this mountainous district is the Sierra Madre del Sur, a steep costal range sloping abruptly into the Pacific. Here in the surroundings of Oaxaca and in the Vlixteca alta, rocks of archaean age and crysta- line shists crop out over an extensive area. Boulders of archaean green stone may have supplied the material for the numerous little stone idols in the Vixteco Typotec style The highland and the Sierra Madre extend South of the Isthmus from Chiapas to Guatemala. The whole of the Chiapas mountain region was formerly the natural fortress of the Chiapanecs, a warlike and very ancient Indian tribe, who maintained their independence against the victorious advance of the Mexican rule. During the Spanish rule Chiapas belonged to Guatemala as the Provincia de San Vicente de Chiapas. The descendants of kindred people duell to the south on both sides of the present state border. Here are also the remnants of an old superior Indian culture common to both countries. Both the shores of the Pacific and the Gulf of Mexico are bordered by narrow or broad coastal plains. The broadest of these belts is the still uninhabited huss steppe at the lower part of the Rio Grande del Norte. This steppe is the southern extension of the Texas coastal pkın. The peninsula of Lower Cali- fornia on the Pacific, the castern mountains of which rise to 2.000 metres, and the peninsula of Yucatan, on the Gulf of Mexico, are mainly reached by sea from the rest of the country. In their somewhat loose connection with the Mexican Suite the retain much that peculiar to their historical and economic development
Although the greater part of Mexico extends south of the Tropic of Cancer. in the tropical Zone, it offers the most varied conditions for vegetation in 10 its ekrated position. It is the clevation above sea level, and not only latitude that determines climate. There is also a great contrast between the humd Athenind und lucilic Coast where artificial irrigation is even MOOCs in the vicinity of the occan (nly the Atlantic winds bring rain. One of the most distincts on the Pacific is the central part of Lower California where freyenth no rain fulls lover Settlements there are oases in the places where und sound streams een dammed and collected behind artiticial walls. The Rio Pato an important waterwany of the oil district, tloss into the Gull of Mexico), as well as the Rio Blanco and Rio Papaloapam (along the
