e may see how the system grew by adapting
the statutes to the customs of the successive frontiers.[10:1] He may
see how the mining experience in the lead regions of Wisconsin,
Illinois, and Iowa was applied to the mining laws of the Sierras,[10:2]
and how our Indian policy has been a series of experimentations on
successive frontiers. Each tier of new States has found in the older
ones material for its constitutions.[10:3] Each frontier has made
similar contributions to American character, as will be discussed
farther on.

But with all these similarities there are essential differences due to
the place element and the time element. It is evident that the farming
frontier of the Mississippi Valley presents different conditions from
the mining frontier of the Rocky Mountains. The frontier reached by the
Pacific Railroad, surveyed into rectangles, guarded by the United States
Army, and recruited by the daily immigrant ship, moves forward at a
swifter pace and in a different way than the frontier reached by the
birch canoe or the pack horse. The geologist traces patiently the shores
of ancient seas, maps their areas, and compares the older and the newer.
It would be a work worth the historian's labors to mark these various
frontiers and in detail compare one with another. Not only would there
result a more adequate conception of American development and
characteristics, but invaluable additions would be made to the history
of society.

Loria,[11:1] the Italian economist, has urged the study of colonial life
as an aid in understanding the stages of European development, affirming
that colonial settlement is for economic science what the mountain is
for geology, bringing to light primitive stratifications. "America," he
says, "has the key to the historical enigma which Europe has sought for
centuries in vain, and the land which has no history reveals luminously
the course of universal history." There is much truth in this. The
United States lies like a huge page in the history of society. Line by
line as we read this continental page from West to East we find the
record of social evolution. It begins with the Indian and the hunter; it
goes on to tell of the disintegration of savagery by the entrance of the
trader, the pathfinder of civilization; we read the annals of the
pastoral stage in ranch life; the exploitation of the soil by the
raising of unrotated crops of corn and wheat in sparsely settled farming
communities; the