Page:The American Indian.djvu/370

306 New World spring from a single stock then the observed deviations of head form are but the normal variations of a biological character.

In a general discussion of the whole subject, Boas states that as the population expanded over the New World, it scattered out into more or less isolated local groups, whose inbreeding soon differentiated varieties of head form and other features. In other words, these were the natural random fluctuations around the fundamental type and are probably not permanent characters, all of which is consistent with their erratic geographic distribution. It may be, therefore, that the longer-headed Algonkins and Patagonians are merely the result of greater marginal isolation rather than survivors of a previous long-headed population.

At the outset, we stated that the New World could make some claim to an intermediate position in head form. If we take the averages of the lengths and breadths of head tabulated on p. 305, we find a length of 175 cm. and a breadth of 141 cm. Martin places the extremes of the world at 143–225 for length, and 101–173 for breadth, from which it appears that our natives are grouped around the middle values. Further, since the extremes in our tables fall short of those for the world as a whole, we are justified in the conclusion that in absolute dimensions of head the New World is truly intermediate, but that in respect to head form as expressed by the cephalic index, approximately the whole known range is found.

The investigations of the Australian school of anthropologists have demonstrated the great comparative significance of the height of the head. We may suspect, therefore, that the native of the New World will show some distinctions in this character, but, as is often the case, sufficient data are not available for a satisfactory conclusion. Martin gives the range of absolute height of skull as 125 to 143 mm. and cites certain Californians as 129, Dakota as 131, and Eskimo as 135. This is not very promising as a definitive character, since we have about the whole range in the New World alone. Further, when we consider the distribution of the recorded values they seem to occur at random over both continents and when all