arrow irrigated fields.
Here native civilization reached its highest grade in North America.
Here desert agriculture achieved something more than a reliable food
supply. It laid the foundation of the first steady integration of
wandering Indian hordes into a stable, permanently organized society.
Elsewhere throughout the North American continent, we see only shifting
groups of hunter and fisher folk, practising here and there a half
nomadic agriculture to supplement the chase.

The primitive American civilization that arose among the Pueblo Indians
of New Mexico and Arizona, the only strictly sedentary tribes relying
exclusively on agriculture north of the Mexican plateau, was primarily a
result of the pressure put upon these people by a restricted water
supply.[617] Though chiefly offshoots of the wild Indians of the northern
plains, they have been markedly differentiated from their wandering
Shoshone and Kiowa kindred by local environment.[618] Scarcity of water
in those arid highlands and paucity of arable land forced them to a
carefully organized community life, made them invest their labor in
irrigation ditches, terraced gardens and walled orchards, whereby they
were as firmly rooted in their scant but fertile fields as were their
cotton plants and melon vines;[619] while the towering mesas protected
their homes against marauding Ute, Navajo and Apache.[620] This thread of
a deep underlying connection between civilization and the control of
water can be traced through all prehistoric America, as well as through
the earliest cultural achievements in North Africa and Asia.

[Sidenote: Economy of the water: fisheries.]

The economy of the water is not confined to its artificial distribution
over arid fields, but includes also the exploitation of the mineral and
animal resources of the vast world of waters, whether the production of
salt from the sea, salt lakes and brine springs, the cultivation of
oyster beds, or the whole range of pelagic fisheries. The animal life of
the water is important to man owing not only to its great abundance, but
also to its distribution over the coldest regions of the globe. It
furnishes the chief food supply of polar and sub-polar peoples, and
therefore is accountable for the far-northern expansion of the habitable
world. Even the reindeer tribes of Arctic Eurasia could hardly subsist
without the sea food they get by barter from the fishermen of the coast.
Norway, where civilization ha