THE MEXICAN CIVILIZATIONS
THE EARLY VALLEY OF MEXICO
ABOUT 2500 years ago the fertile adjoining valleys of Mexico, Puebla, Cuernavaca, and Toluca were already a metropolitan nucleus for the entire northern continent. Other regions in Oaxaca, on the southern Gulf Coast, and in Maya territory were in touch with central Mexico, giving and receiving each in its time. The dominant centre of ancient urban life eventually became the three high intermontane plateau valleys of central southern Mexico, in the quadrant bounded by Tula, Xochicalco, Cholula, and Malinalco. Both Tula and Malinalco bordered the unsettled lands of nomad tribes. Cholula marks a frontier with sedentary peoples of different traditions to the south and east. Xochicalco is an intrusive enclave of Maya style.
Within this quadrant the ancient inhabitants, stimulated by fertile soil, by temperate climate, and by the continual renewal of population through immigration from less favoured regions, changed from nomadic big game hunting (c. 9000 B.C.) to life in early agricultural villages ( 3000-1000 B.C.). Such settlements yielded about 500 B.C. to urban societies not unlike those of ancient Mesopotamia, Egypt, Pakistan, or China.1 Other regions of America transcended central Mexico in elaborating portions of the fabric of its Civilization, but none shows a cultural record of such duration, continuity, or involvement with the rest of ancient America. From central Mexico, styles of art were carried to the south-eastern and south-western United States; to the Maya region; and probably even to the west coast of northern South America.2 No other region of ancient America exerted so continual or so expansive an influence upon its neighbours both near and far.
The earliest dated example of monumental architecture in central Mexico is the circular platform of Cuicuilco (Figure 1) in the Pedregal, near the new University of Mexico. Its four conical stages of large stones laid in clay originally had a diameter of 135 m. (440 feet) and they rose about 20 m. (65 feet). About 500 B.C.3 a sheet of lava enfolded the platform together with the adjoining burial grounds, which have yielded early village manufactures of pottery and clay figurines. The construction of the platform shows two campaigns: two lower stages were built with an altar on top, which was later embedded in two smaller stages. On the east-west diameter a ramp and three short