52 PHYSICAL GEOGRAPHY.

 

pian and Black Seas. It is hilly on the east, but
level on the west. South of the 60th parallel it
is comparatively fertile. Around the shores of
the Arctic are the gloomy Tundras.

The Tundras are vast regions which in summer are
covered with occasional moss-beds, huge shallow lakes,
and almost interminable swamps, and in winter with thick
ice. The tundras are caused as follows: The rivers that
flow over the immense plain of Asia rise in the warmer
regions on the south. Their upper courses thawing while
the lower courses are still ice-bound, permits large quan-
tities of drift ice to accumulate at their mouths, which,
damming up the water, causes it to overflow the adjoining
country.

Depressions of the Caspian and Sea of Aral.—
Two remarkable depressions occur in the basins
of the Caspian and Sea of Aral, and that of the
Dead Sea. These are all considerably below the
level of the ocean. The waters of the Caspian
and Sea of Aral were probably once connected
in a great inland sea.

20,000 “*

 

 

 

The Smaller Asiatic Plains are drained by
several river-systems. These are the Plain of
Mantchooria, drained by the Amoor; the Plain
of China, drained by the Hoang-Ho and the
Yang-tse-Kiang; the Plain of India, drained by
the Indus, the Ganges, the Brahmapootra, and
the Irrawaddy ; and the Plain of Persia, drained
by the Tigris and the Euphrates.

133. Approximate Dimensions of Asia.

Area of continent, 17,500,000 miles.

Coast line, 35,000 miles.

Greatest length from north-east to south-west, 7500 miles.

Greatest breadth from north to south, 5166 miles.
Culminating point, Mount Everest, 29,000 feet.

184. Comparison of the Relief Forms of Eu-
rope and Asia.—In both Europe and Asia the
chief elevations are in the south and the great low
plains in the north. Asia, like Europe, extends
toward the south in three great peninsulas: Ara-
bia, Hindostan, and Indo-China.

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15,000 «* 3 \\
10,000 « A \
5000 id
GSS eS,

 

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Fig. 61, Section of Asia from North to South,
1, Cape Comorin; 2, Deccan; 3, Plain of India; 4, Himalayas; 5, Everest; 6, Kuen-lun; 7, Karakorum; 8, Thibet; 9, Upper Tartary; 10,
Ararat; 11, Elburz; 12, Thian Shan; 13, Altai; 14, Mountains of Kamtchatka; 15, Arctic Ocean, mouth of Yenesei.

 

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Fig. 52, Orographic Chart of Africa,
(Light portions represent mountains; shaded portions, plains.)
1, Abyssinian Plateau; 2, 3, Kenia and Kilimandjaro; 4, Lupata;
5. Dragon; 6, Nieuveldt; 7, Mocambe; 8, Crystal; 9, Cameroons; 10,
Kong; 11, Atlas; 12, Lake Tchad; 13, Madagascar.

 

V. AFRICA.

135. Surface Structure——Nearly the entire con-
tinent of Africa is a moderately elevated plateau.
It therefore has no great low plains; but the in-
terior is lower than the marginal mountain-sys-
tems, and in this respect the true continental type,
high borders and a low interior, is preserved.

136. The Predominant Mountain-System is in
the east.

The Secondary Systems are in the south, west,
and north.

The great interior depression is in the middle,
and is surrounded by the predominant and sec-
ondary systems.
~ A narrow, low plain extends along most of the
coast. It is broadest on the north-west, between
the plateau of the Sahara and the Atlas Moun-
tain-system.

137. The Predominant Mountain-System ex-
tends along the entire eastern shore, from the
Mediterranean Sea to the southern extremity of
the continent. It is highest near the centre, in