s,
moonshine stills, feuds, and a backward population sprung from the same
pure English stock as the Bluegrass people.

[Sidenote: Contrasted environments.]

Here is differentiation due to the immediate influences of environment.
The phenomenon reappears in every part of the world, in every race and
every age. The contrast between the ancient Greeks of the mountains,
coasts and alluvial valleys shows the power of environment to direct
economic activities and to modify culture and social organization. So
does the differences between the coast, steppe, and forest Indians of
Guiana,[213] the Kirghis of the Pamir pastures and the Irtysh River
valley, the agricultural Berbers of the Atlas Mountains and the Berber
nomads of the Sahara, the Swiss of the high, lonely Engadine and those
of the crowded Aar valley.

Contrasted environments effect a natural selection in another way and
thereby greatly stimulate differentiation, whenever an intruding people
contest the ownership of the territory with the inhabitants. The
struggle for land means a struggle also for the best land, which
therefore falls to the share of the strongest peoples. Weaklings must
content themselves with poor soils, inaccessible regions of mountain,
swamp or desert. There they deteriorate, or at best strike a slower pace
of increase or progress. The difference between the people of the
highlands and plains of Great Britain or of France is therefore in part
a distinction of race due to this geographical selection,[214] in part a
distinction of economic development and culture due to geographic
influences. Therefore the piedmont belts of the world, except in arid
lands, are cultural, ethnic and often political lines of cleavage,
showing marked differentiation on either side. Isotherms are other such
cleavage lines, marking the limits beyond which an aggressive people did
not desire to expand because of an uncongenial climate. The distinction
between Anglo-Saxon and Latin America is one of zone as well as race.
Everywhere in North America the English stock has dominated or displaced
French and Spanish competitors down to the Mexican frontier.

As the great process of European colonization has permeated the earth
and multiplied its population, not only the best land but the amount of
this has commenced to differentiate the history of various European
nations, and that in a way whose end cannot yet be definitely predicted.
The best lands have fallen to the firs