RELIEF OF THE LAND 
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Areas composed of ancient archmean rocks, 2. High plains composed of unfolded sedi- 
mentary rocks. 3. Lowlands composed of unfolded sedimentary rocks. 4. Highlands 
and Lowlands mainly composcd of rocks folded in ancient geological periods. 5, Plateaux 
and ranges mainly composed of rocks folded in recent geological enochs. 6, Plaius 
mainly composed of unfolded recent deposits. ; 
N.B.— The structure of areas left blank is unknown. 
Asıa : STRUCTURAL Dıvısıons. (After Herbertson.) 
Relief.—The mountain system of Asia can be divided into (1) the 
ranges that traverse the above-mentioned islands. (2) The belt of 
plateaux and mountain ranges which extends right across the middle of 
the continent, and broadens out in the east to include all between the 
Bering Strait and the Strait of Malacca. This belt forms a serious barrier 
to communication between the triangular plain which occupies West 
Turkistan and most of Siberia in the north, and the river plains of Mesopo- 
tamia, Northern India, and Southern Indo-China. It also separates 
both northern and southern lowlands from the plains of Manchuria and 
China proper in the east. A striking feature of this belt is the east to 
west direction of a series of ranges which traverse it from the Caucasus 
Mountains to the Tsin-ling Mountains of North China. "The area is best 
subdivided into (a) the southern and western plateaux and ranges, and