The human type is always very brachycephalic, with brow receding sharply and long nose making almost one line with the sloping forehead.
The Mississippi valley tribes are nearly brachycephalic; the index increases around the Great Lakes, and lessens farther east.
The eastern Eskimo are dolichocephalic, the western are less so, and the Aleuts brachycephalic. On the North Pacific coast, and in spots down to the Rio Grande, are short heads, but scattered among these are long heads, frequent in southern California, but seen northward to Oregon, as well as in Sonora and some Rio Grande pueblos.
Castren considers them as a mixture of Ugrians with Mongolians, and Zograf as brachycephalic Mongolians.
Measurements of their skulls show them mesocephalic (index about 78), or intermediate between the dolichocephalic and brachycephalic types of mankind.