In view of the evidence presented, there is no need to belabor the point that in the timespan under consideration human impacts overrode natural phenomena, a distinguishing characteristic of the Anthropocene. Most UMI-77 clinical trial proponents of such a chron correlate its onset with the Industrial Revolution, but this would seem justifiable in Tlaxcala only if the effects of rows F, H, and I significantly outweighed all previous historical conjunctures. This is not the case, and land use overrode climate in determining sediment transfers since the local Neolithic Revolution in the 1st millennium BC. But, the post-Conquest era left novel and durable stratigraphic markers

exclusive of the Anthropocene, in rural areas and close to drainage divides, the places least expected by Zalasiewicz et al. (2011). The ubiquituous tepetate surfaces are erosional unconformities that persist in the stratigraphic record. Even after burial, lag deposits of sherds and architectural NLG919 order rubble distinguish them from similar

boundaries formed in pyroclastics before the advent of village life. The cover layer has all the defining attributes of a ‘legacy sediment’ (James, 2013) but is significantly older than examples named as such in the United States. This type of legacy sediment is widespread in other terraced landscapes, characterized by composite, polycyclic and spatially variable soils (Krahtopoulou and Frederick, 2009), but Tlaxcala is the only example I know where it is mapped at regional scales of 1:100,000. It allows the recognition agricultural management even after risers have been erased and the original O-methylated flavonoid slope gradient reestablished. The most predictable way of framing the discussion is in terms of the so-called Columbian debate about the positive or negative impact of indigenous vs. introduced European land use (Butzer, 1993, Crosby, 1972, Crosby, 1986 and Denevan, 1992). In Mexico, it came to be known as the Melville-Butzer controversy (Hunter, 2009), and around the time of the

quincentennial it revolved around arguments for (Melville, 1994) and against (Butzer and Butzer, 1993 and Butzer and Butzer, 1995) a ‘plague of sheep’. In Tlaxcala, the problem has been pondered since its inception. From the perspective of a 16th C. member of the local nobility like Muñoz Camargo, for whom the most valuable asset of a landed estate were its tenants, the epidemics were indeed a disaster to be decried, though he apparently had no qualms about his family’s profits from stocking the vacant land with sheep and cattle (Gibson, 1952, 152; Muñoz Camargo, 2000[1585], 88). Tlaxcala would seem a prime candidate for the ‘plague of sheep’ hypothesis, though historians disagree as to the permanent or transient nature of sheep ranching, and the reliability of Colonial head counts.