Mexico

The northern part of the Sierra Madre Occidental consists of several parallel ranges, the most eastern of which are the Sierra Tarahumare and the Sierra de Durango, while the most western are the Sierra del Nazareno, the Sierra Yaqui and the Sierra Fuerte, all of them converging to form the Sierra del Nayarit. The total length of the former ranges is goo miles. The altitude of this part of the Sierra Madre Occidental rises constantly from north to south, as shown by the height of the culminating peaks, the Alamos, in the north, 5,874 ft. ; the Frailecitos, in the centre, 6,84o ft.; and the Cerro del Pimal, in the Sierra del Nayarit, 11,319 feet. At about 2o° of latitude, corresponding to the geo graphical position of the Nevado de Colima, 14,363 ft., and of the Volcan de Colima, 12,75o ft., the great chain again divides, the western part, or Sierra Madre del Sur, following the shore more or less closely as far as the isthmus of Tehuantepec, and the eastern branch crossing the plateau in a south by east direction.

The Sierra Madre Oriental is narrower and lower, except in its southern part. It rises southwest of Tampico, reaching high altitudes along the western frontier of with the Cofre de Perote, or Naucampatepetl, 13,419 ft., and the magnificent snow-capped cone of Orizaba, or Citlaltepetl, 18,209 feet.

Crossing the highest part of the Mexican plateau is a broken and chaotic series of ranges, uniting the two sierras madres, part of which is sometimes called Cordillera de Anahuac, where rise the Malinche, or Malintzin, 14,636 ft., the gigantic snow-clad cone of the Popocatepetl, 17,888 ft., the Ixtaccihuatl, 17,323 ft., and further west, the Nevado de Toluca, 15,168 feet.

The Sierra Madre del Sur, or Sierra de Oaxaca, of which the only high peak is the Zempoalteped (meaning 20 peaks), 11,139 ft., decreases in height from north to south until it reaches the low lying isthmus of Tehuantepec, the lowest altitude (portillo) of which is 787 ft. (Bose), and the highest point, reached by the trans-isthmian railway, 852 feet. After this interruption the chain, now known as Cordillera de Chiapas, or de Soconusco, is seen to rise again, its summits reaching 7,872 ft., with the cone Soconusco, and 14,00o ft. with the Tacand.

The great peninsula of Lower California, the "fleshless arm of Mexico" (el brazo descarnado de Mexico), as the Mexicans call it, is a rugged region, evidently the continuation of the coast range of the United States, the Gulf of California corresponding to the San Joaquin-Sacramento valley. Its frame is made of four

successive chains with an especially noticeable break in the mid dle, where the extinct volcanic group of Tres Virgenes is found. The highest recorded peak is the Calamahue, or Santa Catalina, 10,122 feet. These coastal ranges can be linked with the Sierra Madre del Sur, through the Tres Marias isles and Cape Corrientes, on the mainland (Gabb, Aguilera, Ord6fiez, Suess).

Volcanoes and Earthquakes.

Starting almost at the border between the United States and Mexico, we find the beginning of a chain of volcanoes that is practically unbroken until it reaches the southern end of South America. The Piriacate, of Sonora, 1,656 ft., is the only one, north of the Lerma river, that shows any activity, but south of that river we find the Ceboruco, 7,100 ft., which was still active in 1875, and the Colima volcanic group, of which the Fuego, 14,200 ft., has had frequent eruptions, the latest being the one of 1909. East of Colima rise the Tancitaro, 12,000 ft., and the famous Jorullo, 4,262 ft., whose first eruption took place in 1759; while north-east of this group we find the Nevado de Toluca or Xinantecatl, 15,00o ft., now quiescent, but whose former eruptions must have been formidable. South-east of the Nevado de Toluca is the Popocatepetl, 17,888 ft., not en tirely extinct, whose crater is 500 ft. deep and 21 m. in circum ference, the craterless (although of volcanic origin) Ixtaccihuatl, 17,323 ft., the above mentioned Malinche, Cofre de Perote, and, finally, the Orizaba, the highest of all, 18,209 ft., probably the most perfect and beautiful of all volcanoes, and comparable to the Peruvian Misti and the Japanese Fuji. South-east of Veracrui is an isolated volcanic group of which the Tuxtla, 4,900 ft., had a terrific eruption in 1793 but is now quiescent. On the Pacific coast the Soconusco, 7,872 ft., smokes occasionally and, right on the border itself, the Tacana, 14,000 ft., is still active.

Earthquakes, of which there were terrific ones in 1474, accord ing to Aztec traditions, are particularly frequent in the Pacific region of Mexico, especially from San Blas to the Guatemalan border, the town of Chilpancingo being generally the spot most affected. In 1909 it was reduced to a mass of ruins, while Aca pulco was almost as badly treated, partly on account of a tidal wave that followed the shock. The city of Tehuantepec is an other place that has been frequently shaken. The Gulf region is rarely affected.