Volcanoes Of North America
Cód:
491_9781406774955
VOLCANOES OF NORTH AMERICA INTRODUCTION IN the present volume the Western Hemisphere is considered as being divided into two portions namely, North and South America. Central America is included in the northern division for the reason that the student of volcanic phenomena finds a break in the volcanic belts which follow the western borders of the two con tinents, at the Isthmus of Darien. The series of active and recently extinct volcanoes forming the major part of the Windward islands, sepa rating the Caribbean Sea from the Atlantic, will not be considered, as it is most intimately associated with the geography and geology of South America. Although Iceland is more closely connected geographically with America than with Europe, its political association with the Old World, and the fact that it has frequently been described by European travellers, make it convenient to omit it from the present discussion. Among the leading physical features of the southern prolongation of the Noith American continent compris ing Mexico and the Central American republics, are numerous still steaming and recently extinct volcanoes, some of which have had their birth since the Spanish conquest. This region also furnishes examples of violent volcanic eruptions, one of which is probably second, in vi INTRODUCTION reference to intensity, among similar events witnessed by civilized man. Many phases of volcanic phenomena occur in the western portion of the United States. The lofty volcanic moun tains of northern California, Oregon, and Washington are among the most beautiful examples of their class to be found in the world. To the eastward of these giant peaks, whose fiery glow has been replaced by the sheen of snow-fields and glaciers, lies a vast lava-covered re gion, the only known parallel of which, in the extent and thickness of the once molten rocks, occurs in north western India. In Alaska volcanic energy is still active, and more than a-pcre of volcanoes have been in eruption since
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