The international geography . rder of fold-mountains,such as the AUeghanies and the Sierra do Paranao. The north-easterncorner of each is formed of a block of Archaean rocks, neither of whichhas apparently sunk below sea-level since the earliest days of geologicalhistory. In both continents a vast basin occurs between the boundinglines of fold-mountains. And the geological history of the two Americashas been aptly summarised as the history of the gradual filling up of twogreat gulfs which occurred between the eastern and western ridges. The Structure of the Old World.—The structure of the OldW
The international geography . rder of fold-mountains,such as the AUeghanies and the Sierra do Paranao. The north-easterncorner of each is formed of a block of Archaean rocks, neither of whichhas apparently sunk below sea-level since the earliest days of geologicalhistory. In both continents a vast basin occurs between the boundinglines of fold-mountains. And the geological history of the two Americashas been aptly summarised as the history of the gradual filling up of twogreat gulfs which occurred between the eastern and western ridges. The Structure of the Old World.—The structure of the OldWorld is less simple, for the land is broader and more complex. Its mainfold-line runs from east to west instead of from north to south. It is usualto associate Europe and Asia as the continent of Eurasia, to which thepart of Africa north of the Sahara is added on biological grounds. Butfrom the standpoint of geomorphology we cannot separate central andsouthern Africa, unless we also exclude the peninsular area of India. The. The Plan of the Earth 41 great land mass of the Old World is divided into two by a belt of fold-mountains which runs from the Atlantic to the Pacific. The southernmargin of this belt follows the Atlas Mountains, crosses Tunisia, and passesnorth of Malta and south of the Greek Archipelago; it continues eastalong the Taurus, bends northward beside the Persian Gulf, and continuesits former direction past Baluchistan and the northern foot-hills of theHimalaya ; then it runs south again across Burma and the Malay Peninsula,and turning eastward once more crosses the Malay Archipelago, until itsinks below the Pacific. This hne divides two regions which have quitedifferent geological structures. South of it is a series of table-lands ofgreat geological stability and antiquity. North of it is a vast tract in whichthe rocks are mostly horizontal or gently inclined, and only violentlycontorted along the lines of the great mountain chains, the directions ofwhich are
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectgeography, bookyear19
