8. Southeast or Southern Woodland: also timbered
9. Southwest: the southern plateau, sub-arid
10. Mexico: from the tropic to Nicaragua.
The only serious divergence of opinion as to distinctness or approximate boundaries might arise in regard to numbers 4 and 5 of this list. The culture of the Mackenzie region is so deficient and colorless that some students have hesitated to set it up as a separate unit. The Plateau culture is also vague as to positive traits. A plausible argument could be advanced apportioning it between the adjacent Northwest, Plains, California, and Southwest cultures. In fact, usage has here been departed from in reckoning the Great Basin, that part of the plateau which is without ocean drainage, with California instead of the Plateau.
Fig. 34. Culture-areas of America. The numbers refer to the names as listed on pp. 336, 338. (Modified from Wissler.)
The Mexican area is less homogeneous than any of the preceding. At least three sub-centers must apparently be recognized within it: those of the Nahua or Aztec, Zapotec, and Maya. The Nahua were politically and economically dominant at the time of discovery, but the Maya center is likely to be the oldest. To it seems due most of the progress achieved in architecture, sculpture, calendry, and writing. The sources of knowledge in the Mexican area are historic and archæological rather than contemporaneously ethnological, and are available through the medium of Spanish writings. Also the phenomena are more diverse and intricate, as is only natural with higher cultures. The consequence is that they are scarcely as well ordered as those from north of Mexico and have not yet been brought into as close a comparable relation with the latter as these among themselves.
South American cultures seem to arrange themselves on fewer lines of cleavage than those of the northern continent. Only five areas are as yet distinctly recognizable. This paucity is perhaps due to a less intensive search for facts and less systematic attempt to classify them, so that future studies may increase the number of areas recognized. Yet a simplicity of plan of culture relationships is evident. The narrow strip between the Andes and the Pacific is a region of rather high culture throughout, the whole remainder of the continent one of much lower and comparatively uniform culture. The areas determined are: