limited to
this area; subsequently its scope was extended to include the whole of
North America north of Mexico. Such an extension of its plan was,
indeed, almost necessary, since a number of important families, largely
represented in the United States, are yet more largely represented in
the territory to the north, and no adequate conception of the size and
relative importance of such families as the Algonquian, Siouan,
Salishan, Athapascan, and others can be had without including
extralimital territory.

To the south, also, it happens that several linguistic stocks extend
beyond the boundaries of the United States. Three families are, indeed,
mainly extralimital in their position, viz: Yuman, the great body of the
tribes of which family inhabited the peninsula of Lower California;
Piman, which has only a small representation in southern Arizona; and
the Coahuiltecan, which intrudes into southwestern Texas. The Athapascan
family is represented in Arizona and New Mexico by the well known Apache
and Navajo, the former of whom have gained a strong foothold in northern
Mexico, while the Tanoan, a Pueblo family of the upper Rio Grande, has
established a few pueblos lower down the river in Mexico. For the
purpose of necessary comparison, therefore, the map is made to include
all of North America north of Mexico, the entire peninsula of Lower
California, and so much of Mexico as is necessary to show the range of
families common to that country and to the United States. It is left to
a future occasion to attempt to indicate the linguistic relations of
Mexico and Central America, for which, it may be remarked in passing,
much material has been accumulated.

It is apparent that a single map can not be made to show the locations
of the several linguistic families at different epochs; nor can a single
map be made to represent the migrations of the tribes composing the
linguistic families. In order to make a clear presentation of the latter
subject, it would be necessary to prepare a series of maps showing the
areas successively occupied by the several tribes as they were disrupted
and driven from section to section under the pressure of other tribes or
the vastly more potent force of European encroachment. Although the data
necessary for a complete representation of tribal migration, even for
the period subsequent to the advent of the European, does not exist,
still a very large body of material bearing upon the subject is at ha