occupied, the number of tribes grouped under them respectively, or the
number of languages and dialects of which they are composed. Some of
them cover wide areas, whose dimensions are stated in terms of latitude
and longitude rather than by miles. Others occupy so little space that
the colors representing them are hardly discernible upon the map. Some
of them contain but a single tribe; others are represented by scores of
tribes. In the case of a few, the term “family” is commensurate with
language, since there is but one language and no dialects. In the case
of others, their tribes spoke several languages, so distinct from one
another as to be for the most part mutually unintelligible, and the
languages shade into many dialects more or less diverse.

The map, designed primarily for the use of students who are engaged in
investigating the Indians of the United States, was at first 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