2 No reference is made to the Paleo-Indian in Meso-America, for it is not possible as yet to link that stage with the later Meso-American sequence.

3 Kidder, 1940, p. 121.

4 At the Round Table Conference in Tuxtla (Gutierrez, 1942), it was maintained that the Olmec style and the origin of the rain god cult is to be ascribed to this period. It is true that the cult probably originated then, but the ceremonial center of la Venta and the complete development of the jaguar symbolism for gods of the earth and water belongs taxonomically, and chronologically as well according to Drucker (1947), to the Florescent period.

5 Apenes, 1943. Chinampas are artificial islands constructed in shallow water for the purposes of horticulture.

6 Noguera, 1943.

7 Ricketson and Ricketson, 1937, pp. 2-3 and 10-12.

8 Thompson, 1931.

9 Compare this situation with the Peruvian coast before the unification brought about by the militaristic expansion, and both areas, Meso-America and Peru, with the highlands of Asia Minor before the unification under the feudal Hittite Empire (see Childe, 1946, pp. 155-6).

10 Compare the tombs of Kaminaljuyu with their sacrified servants and women accompanying an important person with those of the Mochica phase in the Virú Valley.

11 In my presentation of this paper to the “Conference on Peruvian Archaeology,” I included a short Transitional period between the Florescent and Militaristic periods, and it appears as such in the comparative chart developed by Dr. Kroeber. The period was seen as corresponding in the Maya area to the lapse of time between the abandonment of the ceremonial centers of the Peten and the arrival of the Itzas at Chichen, and in central Mexico to the poorly known interval between the fall of Teotihuacan and the rise of Tula. On further consideration, however, and in consultation with Gordon Ekholm, I have decided that it is preferable to exclude such a division as lacking sufficient foundation from the more general cultural point of view.

12 Historically, in the narrow sense of the term, and in addition to the division mentioned in the previous footnote, it is easy to distinguish between the Toltec and Chichimec- Aztec periods in central Mexico, corresponding more or less to the Mexican period and the Mexican absorption period in the Maya area (Thompson, 1943, 1945). Cultural differences in the broad terms of this discussion, however, are not well known.

13 From 9.16.0.0.0 (Maya Long Count) according to finds by Boggs at Tazumal. Boggs, 1945, p. 42.

14 Smith and Kidder, 1943.

15 Collection in Peabody Museum, Harvard University.

16 Verbal communication from Dr. A. M. Tozzer.

17 In these regions the mean annual rainfall is without exception less than 1500 mm. and in some parts less than 500 mm. The number of rainy days is without exception less than 200, in many parts less than 150, and there are areas with less than 50 days with rain per year. Almost all of the precipitation is concentrated in four months, from June to September. These climates correspond to types CB'w, CA'w, BA'w, BB'w, and CA'd of the Koppen and Thornthwaite classification (map in Sanchez, 1936). Under such conditions irrigation will permit more than one annual crop —and greater concentration of population—and such is shown in the available information.

18 Mention is made of metal battle-axes, but carried “por genlileza y a manera de galania” (Bernal Diaz, 1939, Vol. 1, p. 91).

Compared to the Old World, I believe that the taxonomic position from the point of view of the use of metal is generally speaking closer to Childe's Mode 1 than to his Mode 2. It is dubious whether western Mexico is closer to Mode 3, due to the limited number of forms. (See Childe, 1944, p. 4. In Mode 1, weapons and ornaments are made from copper and its alloys, but there are no mutant tools and hardly any implements adapted exclusively to industrial use; in Mode 2, copper and bronze are regularly used in handicraft, but not for rough work, and the metal types include specialized forms; in Mode 3, there is also use of metal in agriculture and for rough work, as well as specialized forms and decline in the lithic industry.)

19 See Thompson, 1943.

20 The ancient forms of human sacrifice were probably flaying, decapitation, and the sacrifice of children in fertility and harvest rites. According to available data the sacrifice of hearts was not practiced before the Toltec epoch. In Aztec times the number of victims slaughtered reached enormous proportions.

21 To illustrate my ideas I list in the following the most typical examples for each period, using as is customary the names of archeological sites or historical names:

Formative. Zacatenco, Ticoman, Lower Tres Zapotes, Mamom.

Florescent. Teotihuacan, Middle and Upper Tres Zapotes, Monte Alban II and III, Esperanza, Tzakol, Tepeu.

Militaristic. Toltec, Chichimec, Aztec, Monte Alban V (Mixteca-Puebla style), Tarascan (Tzintzuntzan), Mexican period and Mexican Absortion period in the Maya area.

22 According to Dr. Caso's as yet unfinished study of the Mixtec genealogies, these go back to about the beginning of the period and may provide an historical base for a more certain chronology.