22 MEXICO, CENTEAL AMERICA, "WEST INDIES. 



Mexico proper. Xot far from the neck of the peninsida the system culminates in 

 Mount Calamahue, or Santa Catalina, terminating in a peak white as snow and 

 rising 10,000 feet above the sea. 



The northern chain, which skirts the Pacific coast, ends north of the spacious 

 Sebastian Yiscuino Bay, beyond which it merges through gently inclined plateaux 

 in a ridcre rising above the eastern shores of Lower California. These mountains, 

 which are of tertiary formation, are interrupted by deep ravines, beyond which 

 rises the volcanic group of the Très Virgenes (" Three Virgins "), situated almost 

 exactly in the middle of the peninsula, which has a total length of about 1,300 

 miles. The peaks of this group appear scarcely to exceed 6,600 feet, though 

 raised by some authorities to 7,250 feet. But considerable discrepancies occur in 

 the elevations given by different writers for most of the Mexican mountains. 



No eruption has taken place since 1857 in the Très Virgenes group, where 

 nothing has been noticed except some vapours rising from the crevasses. All the 

 other volcanoes in Lower California are extinct, mineral and thermal springs, with 

 a few solfataras, being the only evidences of underground activity. West of the 

 io-neous group a chain of hills traverses the peninsula at an altitude of 3,450 

 feet, and is continued seawards by some lofty islands at its north-west extremity. 



South of the Très Virgenes a ridge of tertiary sandstones, falling abruptly 

 eastwards and presenting a gentle incline towards the Pacific, extends as far as 

 La Paz Bay. But despite its name, the Cerro de la Giganta, the culminating 

 point falls below 4,600 feet, while the mean height of the ridge appears to be little 

 more than 3,000 feet. The extremity of the peninsula south of La Paz forms a 

 sort of granitic island terminating in two parallel crests, one of which has an extreme 

 height of 6,220 feet. Mineral deposits, including gold, silver, copper, and iron, 

 occur in nearly all these coast ranges ; gold prevails in the schists of the west 

 coast, silver ores chiefly in the porphyries on the opposite side. 



Lower or South California, however, notwithstanding its narrow width, 

 rendering it easily accessible to travellers, is a comparatively unknown region 

 owing to its excessive dryness and scanty population. The mountain heights have 

 for the most part only been measured or estimated at a distance by marine surveyors. 

 Mariners also have chiefly studied the character of the coasts, one, washed by the 

 Gulf of California, steep and rocky, the other falling in gentle inclines towards 

 the Pacific Ocean, which in many places is fringed by low beaches and sandy 

 islets. The ranges on the east side rise precipitously above the profound chasm, 

 through which the sea has penetrated far inland between Mexico and the peninsula. 



The islands on the east side are disposed in a perfectly parallel axis with the 

 peninsular ranges, and rise to considerable heights. Angel de la Guardia, amongst 

 others, has an elevation of 4,320 feet, and collectively these islands of Lower 

 California have a greater extent than all the other Mexican islands taken together. 



Intersected by the straight line forming the geometrical frontier of Arizona, 

 the various chains, which are limited northwards by the depression of thePio Gila, 

 penetrate into the territory of Sonora and Chihuahua in parallel ridges with a 

 south-eastern trend. These various ranges are collectively grouped under the 



