Physical geography. By Mary Somerville ...

38 PHYSICAL GEOGRAPIIY. CHAP. II.
CHAPTER II.
Direction of the Forces that raised the Continents -Proportion of Land
and Water-Size of the Continents and Islands-Outline of the LandExtent of Coasts, and proportion they bear to the Areas of the Continents-Elevation of the Continents- Forms of Mountains- Forms of
Rocks - Connexion between Physical Geography of Countries and their
Geological Structure - Contemporaneous Upheaval of parallel Mountain
Chains - Parallelism of Mineral Veins or Fissures - Mr. Hopkins's
Theory of Fissures - Parallel Chains similar in Structure - Interruptions in Continents and Mountain Chains-Form of the Great Continent
-The High Lands of the Great Continent-The Atlas, Spanish, French,
and German Mountains-The Alps, Balkan, and Apennines-GlaciersGeological Notice.
AT the end of the tertiary period the earth was much in the same
state as it is at present with regard to the distribution of land and
water. The preponderance of land in the northern hemisphere indicates a prodigious accumulation of internal energy under these
latitudes at a very remote geological period. The forces that raised
the two great continents above the deep, when viewed on a wide
scale, must evidently have acted at right angles to one another,
nearly parallel to the equator in the old continent, and in the direction of the meridian in the new; yet the structure of the opposite
coasts of the Atlantic points at some connexion between the two.
The mountains, from their rude and shattered condition, bear
testimony to repeated violent convulsions similar to modern earthquakes; while the high table-lands, and that succession of terraces
by which the continents sink down from their mountain-ranges to
the plains, to the ocean, and even below it, show also that the land
must have been heaved up occasionally by slow and gentle pressure,
such as appears now to be gradually elevating the coast of Scandinavia and many other parts of the earth. The periods in which
these majestic operations were effected must have been incalculable,
since the dry land occupies an area of nearly 38,000,000 of square
miles.
The ocean covers nearly three-fourths of the surface of the globe,
but the distribution is very unequal, whether it be considered with
regard to the northern and southern hemispheres, or the eastern and
western. Independently of Victoria Land, whose extent is unknown,
the quantity of land in the northern hemisphere is three times
greater than in the southern. In the latter it occupies only one