rse, that trading of this sort to Mexico
was not altogether a new thing. Sutlers of the old fur traders and
trappers already had found the way to New Spain from the valley of the
Platte, south along the eastern edge of the Rockies, through Wyoming
and Colorado. By some such route as that at least one trader, a French
creole, agent of the firm of Bryant & Morrison at Kaskaskia, had
penetrated to the Spanish lands as early as 1804, while Lewis and Clark
were still absent in the upper wilderness. Each year the great mountain
rendezvous of the trappers--now at Bent's Fort on the Arkansas, now
at Horse Creek in Wyoming, now on Green River in Utah, or even farther
beyond the mountains--demanded supplies of food and traps and ammunition
to enable the hunters to continue their work for another year. Perhaps
many of the pack-trains which regularly supplied this shifting mountain
market already had traded in the Spanish country.

It is not necessary to go into further details regarding this primitive
commerce of the prairies. It yielded a certain profit; it shaped the
character of the men who carried it on. But what is yet more important,
it greatly influenced the country which lay back of the border on the
Missouri River. It called yet more men from the eastern settlements
to those portions which lay upon the edge of the Great Plains. There
crowded yet more thickly, up to the line between the certain and the
uncertain, the restless westbound population of all the country.

If on the south the valley of the Arkansas led outward to New Spain,
yet other pathways made out from the Mississippi River into the unknown
lands. The Missouri was the first and last of our great natural frontier
roads. Its lower course swept along the eastern edge of the Plains, far
to the south, down to the very doors of the most adventurous settlements
in the Mississippi Valley. Those who dared its stained and turbulent
current had to push up, onward, northward, past the mouth of the Platte,
far to the north across degrees of latitude, steadily forward through
a vast virgin land. Then the river bent boldly and strongly off to the
west, across another empire. Its great falls indicated that it headed
high; beyond the great falls its steady sweep westward and at last
southward, led into yet other kingdoms.

When we travel by horse or by modern motor car in that now accessible
region and look about us, we should not fail to reflect on the long
trail of the u