Intensive agriculture and socio-political development in the Lake Patzcuaro Basin, Michoacan, Mexico.

Fisher, Christopher T. ; Pollard, Helen P. ; Frederick, Charles 等

Introduction

Intensive agriculture played a pivotal role in the development of archaic states, but there is considerable debate concerning its relationship to population growth, climatic variability, and centralization. One important example is that of the Tarascan State (Lake Patzcuaro Basin, Michoacan, Mexico (Pollard 1997) [ILLUSTRATION FOR FIGURE 1 OMITTED].

Newly discovered intensive wetland features, in the form of canals and associated agricultural fields, allow the intensification question to be assessed in this region for the first time. This new research examines the relationship between intensification, demography, environmental variability, and the emergence of social complexity for the pre-Tarascan period. Relict agricultural features are an amalgam of socio-economic process and landscape manipulation requiring multiple lines of archaeological and environmental data to decode. This synthesis is best accomplished through a landscape approach.

Intensification in perspective

Two types of intensification approaches can be defined based on core assumptions [ILLUSTRATION FOR FIGURE 2 OMITTED]. The first, the top down and the bottom up type of approach (Chambers 1980; Erickson 1993a; Scarborough 1991) debates who, and with what resources, was able to construct water-management features. The more traditional and most often applied top down approach, following the hydraulic hypothesis (Wittfogel 1957), suggests that the complexity, large scale, technological sophistication and massive labour requirements of intensive agriculture require co-ordination, planning, management and possibly coercion, most often by the state (Kolata 1996; Matheny & Garr 1983; Sanders et al. 1979; Stanish 1994). In this view, only state-level societies are capable of absorbing the presupposed high labour, capital, and administrative costs.

Recent archaeological research has come to re-examine the top down approach. Excavation and survey within the Lake Titicaca Basin (Erickson 1993a; Graffam 1992) has identified extensive tracts of raised fields and associated settlements that can be securely dated to periods that precede and post-date regional integration by the Tiwanaku state. These systems also initially evolved and persisted in the absence of population or other stresses. Raised-field and canal systems have also been located prior to regional integration contexts in other areas of Latin America (Doolittle 1990; Sluyter 1994). This has led Erickson to argue that raised-field farming was organized locally, producing, over time, a totally human-made landscape (1993a: 371).

The second type of approach is composed of explanations emphasizing differing evolutionary mechanisms for the adoption of agricultural intensification. Either a prime mover (push) or political economy (pull) based approach provides the impetus for intensification. The push-based mode assumes that prehistoric farmers participate in a labour-intensive mode of subsistence as a response to some sort of resource imbalance, most often demographic. Thus, in this prime-mover-orientated approach, population pressure (Boserup 1981; Sanders et al. 1979; Turner et al. 1977), becomes an evolutionary mechanism that is seen as a prerequisite for intensive agricultural systems. In recent literature the systemic relationship between population growth and agricultural intensification first proposed by Boserup (1965) has been critically examined. As a result there is a growing body of archaeological literature that suggests the lack of a causal link between demographic stress and agricultural intensification (e.g. Blanton et al. 1982; Brumfiel 1976; Feinman et al. 1985; Kowalewski et al. 1989).

Political-economy-based explanations assert that intensification is a response to socio-economic systems promoting predictable surplus to facilitate kin-based exchange, risk management, craft specialization and lineage-based demands for tribute (Brumfiel & Earle 1987; D'Altroy & Earle 1985; Price & Feinman 1995; Wright 1984). The crux of the difference between prime-mover and political-economy-based perspectives is the emphasis placed on either external or internal mechanisms of evolution. In the push mode the locus of change is located outside the socio-economic sphere of human control in an intrinsically expanding population. In contrast, political-economy models see intensification as the result of human-driven strategies for agricultural surplus. In this view intensification is promoted by emerging elites to finance the acquisition of power.

Both approaches to intensification have distinct implications for Patzcuaro prehistory. For the top down and bottom up perspectives construction timing is critical. Following the top down approach intensive agricultural features would depend on, and date closely to, the political unification and economic integration of the Patzcuaro Basin by the Tarascan state. In the bottom up perspective, agricultural features should pre-date basin integration. A second set of indicators follow the political-economy approach. Intensive agricultural features should be associated with emerging elites and the early development of complex society. Support for the adoption of intensive agriculture as a response to resource imbalance is recognized, if construction of features generally coincided with such perturbations.

Lake Patzcuaro: background

Lake Patzcuaro is a shallow, highland lake on the Central Mexican Altiplano (Chacon 1993) whose basin shares many characteristics with the more familiar Basin of Mexico (elevation, vegetation, monsoonal climate). There are some important differences, since the Lake Patzcuaro Basin is smaller (928 sq. km) than the Basin of Mexico (7000 sq. kin) and receives almost twice as much rainfall (900-1250 mm/year Patzcuaro, 450-1000 mm/year Basin of Mexico (West 1948)).

Much of the significant palaeoenvironmental research undertaken in Central Mexico in the last decade (Metcalfe et al. 1989; O'Hara et al. 1993; 1994; Street-Perrot et al. 1989) has been within the Patzcuaro Basin. Since Lake Patzcuaro occupies a closed basin it is considered an amplifier lake and is highly susceptible to minor climate changes. A very small decrease in overall rainfall combined with a concomitant increase in temperature and evapo-transpiration rates can result in lake-level differences of [greater than]2 m per annum (West 1948). Minor climatic fluctuations and resulting shifts in lake level, perhaps exacerbated by human environmental modification, have occurred with some frequency in the past. Recent research has focused on a variety of lake cores recovered from the Mexican Highlands suggesting a series of droughts for the Patzcuaro Basin between [TABULAR DATA FOR TABLE 1 OMITTED] AD 700 and 1100 (O'Hara 1993; O'Hara et al. 1994). This would have resulted in a regression episode estimated to have been between 10-13 m below the level of the lake at the time of European contact.

The prehistory of the Basin

Prior to the formation of the Tarascan state in the 1350s little is known about the prehistory of the Patzcuaro region. Two recent archaeological projects in the southwest corner of the Patzcuaro Basin yield the only substantive data. The first is a full-scale survey of a 150-sq.-km area between the modern towns of Patzcuaro and Erongaricuaro [ILLUSTRATION FOR FIGURE 1 OMITTED] (Pollard 1998), and the second are excavations from the sites of Urichu and Jaracuaro (Pollard 1995). Much of this background is summarized from these two projects (TABLE 1). In addition a CEMCA project of survey and excavation from the Zacapu basin (Michelet 1992) provides critical background information for a neighbouring region.

The earliest occupation evidence comes through the presence of maize pollen in lacustrine cores dated to 1500 BC. In the Late Preclassic period ([greater than]AD 350) small village societies are known from the adjacent Cuitzeo and Zacapu Lake Basins. No evidence of these lacustrine-orientated communities has yet been found within the Patzcuaro Basin (Pollard 1997).

For the West Central Highlands, a major shift in socio-political organization begins in the Classic Period (AD 400-900) marked by increasing extra-regional economic ties. Large, well-planned ceremonial centres appear such as Tres Cerritos near the Cuitzeo lake Basin, Tingambato, located just outside the Basin, and Urichu, located in the southwest portion of the Lake Basin. These settlements contain ball courts, mound groups with sunken plazas, and group tombs with exotic items. Evidence of increasing social complexity includes a large group tomb at Urichu containing multiple individuals associated with exotic grave goods (c. AD 400). In addition to Urichu, several centres greater than 40 ha in size also emerge in the southwest portion of the Lake Basin. In the neighbouring Zacapu Basin the Classic period is associated with an expansion of smaller settlements away from the lakeshore (Michelet 1992). For Patzcuaro sites under 20 ha occur only on the three islands found within the survey area located away from the Prehispanic shoreline. Severe upland erosion and lakebed sedimentation seen in later prehistory is responsible for this disparity.

The Early/Middle Postclassic (AD 900-1350) marked another major shift in socio-political organization, due in part to a breakdown of Classic-period exchange networks and a re-organization of the Mexican Highlands. Large, nucleated, defensible sites, such as El Palacio in Zacapu (Michelet 1992) appeared while many smaller, less protected sites were abandoned. In Patzcuaro (Early Urichu Phase (AD 900-1100)), there was growth or expansion of major defensible upland centres and abandonment of much of the lake shore. This trend ended in the late Middle Postclassic (AD 1100-1350) with a major explosion in the location and size of settlements. The Late Urichu period (AD 1100-1350) marked the beginnings of centralization, social stratification and economic integration leading to the formation of the Tarascan state in the Late Postclassic (AD 1350-1525). Sites appeared in less defensible locations, such as the lakeshore zone, and new areas of the uplands were colonized. Large, truly urban centres grew dramatically in size and complexity with new zones of monumental construction. This trend intensified during the Tariacuri phase (AD 1350-1525), with the formation of the Tarascan state.

Evidence for agricultural intensification

In 1996, we initiated a programme of landscape research within the southeast portion of the Lake Basin to locate, characterize and date Prehispanic agricultural features [ILLUSTRATION FOR FIGURE 1 OMITTED] (1998). A drop in the level of Lake Patzcuaro over the last decade allowed our investigation to centre on the shallow Prehispanic lake margin - an area especially sensitive to fluctuations in water level. During the early Hispanic period large-scale landscape abandonment led to massive erosion blanketing much of this area with up to 4 m of redeposited upland sediment (Fisher 1999). Thus no trace of the Prehispanic lakebed was visible on the surface. Mechanical trenches were excavated in areas thought likely to contain agricultural features (e.g. Erickson 1993b; 1994; Nichols & Frederick 1993); two (NT-2 and NT-3, [ILLUSTRATION FOR FIGURE 3 OMITTED]) contained evidence for canals and associated agricultural horizons. To provide context, 16 locations from the immediate region, along with an additional trench (NT-1; excavated 1 km south of NT-2 and NT-3 on the former lakebed), were examined [ILLUSTRATION FOR FIGURE 1 OMITTED]. Comparison between these non-modified sequences and the trenches containing canals allowed us to identify anthropogenic soils and sediments.

A typical exposure in this region showed a very similar sequence of deposition related to both episodes of lake-level change and human-induced erosion [ILLUSTRATION FOR FIGURE 2 OMITTED]. A tuff, composed of reworked lake sediments (diatomite) and volcanic ash underlies the study area. This is followed by an organic-rich marsh soil (IX). Above this is a Prehispanic erosion episode, composed of laminated clayey upland sediments ([ILLUSTRATION FOR FIGURE 3 OMITTED], NT-1) covered by a second marsh (VIII). The thickness and composition of these rythmites - deposited in open water - varies by proximity to archaeological sites. The prehispanic portion of the sequence is then capped with a third marsh soil (V) and buried under eroded upland sediment deposited during the Hispanic period. These exposures can now serve as a baseline to help detect anthropogenic modification.

Trenches containing agricultural features were atypical from adjacent exposures in two respects [ILLUSTRATION FOR FIGURE 3 OMITTED]. Surrounding the middle marsh (VIII) are two discontinuous bands of organic-rich, iron-cemented sediment (VII). These iron pans were either formed from the accumulation of precipitates through ponding or from continual wetting and drying of the soil - both an indicator of fluctuating water conditions.

A second discordance noted for NT-2 and NT-3 are the lack of rythmites formed from Prehispanic eroded sediment seen in related profiles. What appears instead is a clayey, organic-rich, homogenous soil (VI). The formation of an incipient argillic horizon at the base of this soil indicates the translocation of clay in a non-inundated environment making this a third drying episode. In general character this zone is strikingly similar to modern agricultural soils formed from similar parent materials, suggesting a buried agricultural horizon. Cultural material was present throughout the sequence up to the highest marsh (V). Ceramics recovered were consistent with a Classic period occupation but not phase specific.

Seven AMS dates were submitted from this locality with a tight distribution between AD 120 and AD 850 as shown in FIGURE 3 (AD ages are the intercept of radiocarbon age with calibration curve, see Stuiver et al. 1993). Five of these dates form a column from the earliest canal feature in NT-2 and two come from the lower portion of the sequence in NT-3. A date of AD 120 (1890[+ or -]40 b.p. Beta-102812) was obtained from NT-3 on the contact between the first iron zone and the basal marsh (IX) marking the inception of a drying trend. The base of the second iron pan dates to AD 605 (1480[+ or -]40 b.p. Beta-102813) effectively bracketing the middle marsh (VIII). Dates of AD 680 (1330[+ or -]40 b.p. Beta-102805) and AD 775 (1260[+ or -]40 b.p. Beta-102807) were obtained from the middle and top of the second iron zone (VII). The column ends with a determination of AD 885 (1170[+ or -]40 b.p. Beta-102811) recovered roughly one third of the way from the bottom of the clayey agricultural soil (VI). This dated sequence records rapid and constant fluctuations in the level of Prehistoric Lake Patzcuaro for most of the Classic period. Between AD 120 and AD 775 two low lake stage events (the two iron cemented zones - VII) and one higher stage episode (the middle marsh - VIII) are present. Above AD 775 a long-term regression of the lake is evidenced by the formation of the clayey soil (VI). This is buried by the final marsh (V) representing the Late Postclassic high stage recorded in the ethnohistoric literature (O'Hara 1993; Pollard 1993) and documented by the work of O'Hara et al. (1994).

The relatively short temporal span of the deposition sequence from the Nocutzepo series of trenches suggest abrupt and rapid lake-level changes. These data support aspects of the lake stage model presented by O'Hara et al. (1993, 1994) for Lake Patzcuaro in that a lake transgression is clearly evident in the Early Postclassic as they suggest. Problematic, however, is the failure of their core data to pick up the earlier episodes of lake-level flux in the Classic period. Thus this study should serve as a cautionary tale for those who rely on large-scale climatic or other sets of data as proxies for local records of environmental change (e.g. Kolata 1996).

Having established the general sequence of deposition and the manner of human modification we can now discuss the agricultural features discovered in 1996. Two episodes of canal building were present in the Nocutzepo trenches. Canals extended across trench walls and were filled with combinations of marsh, laminated silts or iron-pan sediments. The earliest canal [ILLUSTRATION FOR FIGURE 3 OMITTED], roughly a metre wide, was excavated into the basal marsh (IX), filled with the first iron pan episode (VII), and then capped with the second marsh (VIII) before AD 590 (1500[+ or -]40 b.p. Beta-102811)

Above this feature are two later canals excavated into the clay rich soil (VI) and filled with the final marsh (V). These features are roughly 3 m apart and between 40 cm and over i m wide. Between the two canals is an organic-rich zone that is either an agricultural soil or zone of spoil from the adjacent canals.

A 5-m-long tangential trench was also excavated at this site to define the overall morphology of the area, resulting in a T-shaped plan. The sequence of deposition is the same for NT-2 and NT-3 but the distribution of sediments differs in several key respects. The iron pan (VII) and middle marsh (VIII) zones occur only on the outer edges of the profile. They are replaced in the centre by the clayey agricultural soil (VI) which rests directly on the basal marsh (IX). Thus these zones were deposited against what may have been a raised planting platform related to the upper set of canals.

Palaeobotanical samples indicate the presence of maize, based on cob phytoliths, for agricultural levels above the basal marsh (IX). Also discovered were possible root crops and unknown seed or fruit resources (Deborah Pearsall, pers. comm.). The general sequence of sediments, morphology, presence of cultigens and characteristics of these features strongly suggest an agricultural origin. Indeed they are very similar to wetland agricultural features reported throughout Latin America (Erickson 1993a; Kolata 1996; Nichols & Frederick 1993; Parsons et al. 1985; Sluyter 1994). Whether they represent true Chinampas or are a local wetland agricultural adaptation such as reported by Foster (1948) and West (1948) for the region is still a matter of debate.

Discussion and conclusion

Timing is critical for an evaluation of agricultural intensification within the Patzcuaro Basin. The earliest canal appears between AD 120 and 590 in the Classic period during the Lupe and Jaracuaro phases. This is well before Basin integration by the Tarascan state in the 1350s. These data confirm Erickson (1993a) that state-level control is not necessary for the construction and maintenance of intensive water-control features. The second set of canals post-date AD 885, placing their construction in the early to middle Postclassic (Urichu phase). For Patzcuaro this was a period of increasing socio-political and socio-economic complexity just prior to state formation. This would support aspects of the top down perspective in that some elements of state control were in place - although at a much limited scale.

This research is more straightforward for the stress-based and political-economy approaches. Following Boserup and others, intensive agriculture developed as a response to population pressure. For Patzcuaro, this would mean that intensification should be associated with major settlement expansion in the late Postclassic during the Late Urichu and Tariacuri phases (TABLE 1). Since both sets of agricultural features occurred during the relatively low population densities of the pre-Tarascan period, agricultural intensification was not related to demography in the Patzcuaro Basin.

Following the political-economy perspective, intensive agricultural features should be associated with emerging elites. The early canal appeared during the Jaracuaro and Lupe phases, the first major period of elite development noted for the Basin. The second set of canals occurred during the La Joya/Early Urichu phases, a second major episode of elite development that set the stage for the formation of the Tarascan state. This evidence supports the political economy perspective for intensification.

This paper used a landscape perspective to integrate multiple lines of archaeological and geological data to address a substantive anthropological issue in archaeology: the origins of agricultural intensification. By treating the landscape as an artefact multiple causal explanations were evaluated to place newly discovered water-management features within the Lake Patzcuaro Basin in socio-economic context. Thus agricultural intensification for Patzcuaro is associated with emerging elites as they attempt to consolidate or increase their power. These features also existed prior to state-level control and management being organized instead from the bottom up. It appears that for the Lake Patzucaro Basin, intensive agriculture was firmly established well before Tarascan state formation. In this sense Patzcuaro enters a debate currently centred on the Lake Titicaca Basin, a region with which it shares many characteristics. Both experience extreme shifts in lake level, have lacustrine-orientated societies and were important centres of Prehispanic civilization. In addition, the successive series of canals and agricultural soils from Patzcuaro suggest landscape modification designed to mitigate the effects of a highly variable environment in a scenario not unlike that outlined by Erickson (in this volume of ANTIQUITY). The expansion of a landscape approach to other highland lake basins in Latin America could make great inroads to our understanding of the agrarian foundations of Precolumbian civilization.

Acknowledgements. Much of this paper was presented in the symposium 'Dynamic landscapes and socio-political process: the topography of anthropogenic environments in global perspective', organized by Christopher T. Fisher and Tina L. Thurston at the 63rd meeting of the Society for American Archaeology, Seattle (WA), 1998. We would like to thank Gary Feinman and Barbara Bender for many useful comments. This research was made possible through the generous support of the National Science Foundation with a grant (SBR 950-7673) to Pollard supporting the field research and a Dissertation Improvement Grant (SBR 963-3745) to Fisher for the laboratory analysis. This research would not have been possible without the long-term support of Helen Pollard. Finally, Fisher and Frederick would like to thank the many residents of the Patzcuaro Basin who often helped two muddy gringos get their samples into the van just before the daily rain. Responsibility for omissions and errors lies with Fisher, due no doubt, to the many long hours spent officiating B.C. Society meetings.

References

BOSERUP, E. 1965. The conditions of agricultural growth: the economics of agrarian change under population pressure. Chicago (IL): Aldine.

1981. Population and technological change: a study of long-term trends. Chicago (IL): University of Chicago Press.

BRUMFIEL, E. 1976. Regional growth in the eastern Valley of Mexico: a test of the 'population pressure' hypothesis, in K.V. Flannery (ed.), The early Mesoamerican village: 234-49. New York (NY): Academic Press.

BRUMFIEL, E. & T. EARLE (ed.) 1987. Specialization, exchange, and complex societies. Cambridge: Cambridge University Press.

CHACON, A.T. 1993. El Lago de Patzcuaro, Michoacan, Mexico. basque limnologico de un lago amenazado. Marella: Universidad Michoacana.

CHAMBERS, R. 1980. Basic concepts in the organization of irrigation, in W.E. Coward, Jr (ed.), Irrigation and agricultural development in Asia: perspectives from the social sciences: 28-50. Ithaca (NY): Cornell University Press.

D'ALTROY, T. & T. EARLE. 1985. State finance, wealth finance, and storage in the Inka political economy, Current Anthropology 26:187-206.

DALAN, R.A. & S.K. BANNERJEE. 1998. Solving archaeological problems using techniques of soil magnetism, Geoarchaeology 13: 3-36.

DOOLITTLE, W. 1990. Canal irrigation in pro-historic Mexico: the sequence of technological change. Austin (TX): University of Texas Press.

ERICKSON, C.L. 1993a. The social organization of prehispanic raised field agriculture in the Lake Titicaca Basin, in Scarborough & Isaac (ed.): 367-424.

1993b. Archaeological methods for the study of ancient landscapes of the LLanos de Mojos in the Bolivian Amazon, in P. Stahl (ed.), Archaeology in the American tropics: current analytical method and applications: 1-40. Cambridge: Cambridge University Press.

1994. Methodological considerations in the study of ancient Andean field systems, in N. Miller & K. Gleason (ed.), The archaeology of garden and field: 111-53. Philadelphia (PA): University of Pennslyvania Press.

FEINMAN, G.M., S. KOWALEWSKI, L. FINSTEIN, R. BLANTON & L. NICHOLAS. 1985. Long-term demographic change: a perspective from the Valley of Oaxaca, Mexico, Journal of Field Archaeology 12: 333-62.

FISHER, C.T. 1999. Tariacuri's or Vasco de Quiroga's mess? Prehistoric empire building, colonialism, and the Western Mexican landscape. Paper presented at the 64th annual meeting of the Society for American Archaeology, Chicago.

FOSTER, G.M, & G. OSPINA. 1948. Empire's children: the people of Tzintzuntzan. Washington (DC): Smithsonian Institution.

GRAFFAM, G. 1992. Beyond state collapse: raised fields and pastoral finanace in the south Andes, American Anthropologist 94: 882-904.

KOLATA, A. (ed.). 1996. Tiwanaku and its hinterland: archaeology and paleoecology of an Andean civilization. Washington (DC): Smithsonian Institution Press.

KOWALEWSKI, S.A., G.M. FEINMAN, L. FINSTEIN, R. BLANTON & L. NICHOLAS. 1989. Monte Alban's hinterland, part II: prehispanic settlement patterns in Tlacolula, Etla, and Ocotlan, the Valley of Oaxaca, Mexico. Ann Arbor (MI): University of Michigan Museum. Memoir 23.

MATHENY, R.T. & D. GARR. 1983. Variation in prehispanic agricultural systems of the New World, Annual Review of Anthropology 12: 79-103.

METCALFE, S.E., F.A. STREET-PERROTT, R.B. BROWN, P.E. HALES, R.A. PERROTT & F.M. STEININGER. 1989. Late Holocene human impacts on lake basins in Central Mexico, Geoarchaeology 4: 119-41.

MICHELET, D. 1992. El centro-norte de Michoacan: caracteristicas generales de su estudio arqueologico regional, in D. Michelet (ed.), El proyecto Michoacan 1983-1987: medio ambiente e introduccion a los trabajos arqueologicos:12-46. Mexico (DF): Centre d'Etudes Mexicaines et Centramericaines.

NICHOLS, D.L. & C.D. FREDERICK. 1993. Irrigation canals and Chinampas: recent research in the northwest Basin of Mexico, in Scarborough & Isaac (ed.): 123-51.

O'HARA, S. 1993. Historical evidence of fluctuations in the level of Lake Patzcuaro, Michoacan, Mexico, over the last 600 years, Geographical Journal 159:51-62.

O'HARA, S., S. METCALFE & A. STREET-PERROT. 1994. On the arid margin: the relationship between climate, humans, and the environment. A review of evidence from the high-lands of Central Mexico, Chemosphere 29: 965-81.

O'HARA, S.L., F.A. STREET-PERROTT & T.P. BURT. 1993. Accelerated soil erosion around a Mexican highland lake caused by Prehispanic agriculture, Nature 363: 48-51.

PALERM, A., & E.R. WOLF. 1957. Ecological potential and cultural development in Mesoamerica, Pan American Union Social Science Monograph 3: 1-37.

PARSONS, J., M. PARSONS, V. POPER & M. TAFT. 1985. Chinampa agriculture and Aztec urbanization in the Valley of Mexico, in I.S. Farrington (ed.), Prehistoric intensive agriculture in the Tropics: 49-96. Oxford: British Archaeological Reports. International series 232.

POLLARD, H.P. 1993. Tariacuri's legacy, the prehispanic Tarascan State. Norman (OK): University of Oklahoma Press. 1995.

Estudio del surgimiento del Estado Tarasco: investigaciones recientes, in E. Williams & P.C. Weigand (ed.), Arqueologia del Occidente y Norte de Mexico: 29-65. Zamora: El Colegio de Michoacan.

1997. Recent research in West Mexican archeology, Journal of Archaeological Research 5: 345-84.

1998. Emergence of the Tarascan State: the Urichu, Xaracuaro, and Pareo polities. Unpublished report to the Instituto Nacional de Antropologia e Historia, Department of Anthropology, Michigan State University

PRICE, T.D. & G.M. FEINMAN (ed.). 1995. Foundations of social inequality. New York (NY): Plenum

SANDERS, W.T., J.R. PARSONS & R.S. SANTLEY. 1979. The Basin of Mexico: ecological processes in the evolution of a civilization. New York (NY): Academic Press.

SCARBOROUGH, V. 1991. Water management adaptations in nonindustrial complex societies: an archaeological perspective, in M. Schiffer (ed.), Archaeological method and theory 3: 101-54. Tucson (AZ): University of Arizona.

SCARBOROUGH, V. & B. ISAAC (ed.). 1993. Economic aspects of water management in the New World. Greenwich (CT): JAI Press. Research in Economic Anthropology Supplement 7.

SLUYTER, A. 1994. Intensive wetland agriculture in Mesoamerica: space, time, and form, Annals of the Association of American Geographers 84: 557-84.

STANISH, C. 1994. The hydraulic hypothesis revisited: Lake Titicaca Basin raised fields in theoretical perspective, Latin American Antiquity 5: 312-32.

STREET-PERROTT, F.A., R.A. PERROTT & D.D. HARKNESS. 1989. Anthropogenic soil erosion around Lake Patzcuaro, Michoacan, Mexico, during the Proclassic, Late Postclassic, and Hispanic Periods, American Antiquity 54: 759-66.

STUIVER, M., A. LONG, R.S. KRA & J.M. DEVINE. 1993. Calibration, Radiocarbon 35: 1.

TURNER, B.L., R.Q. HANHAM & A.V. PORTARARO. 1977. Population pressure and agricultural intensity, Annals of the Association of American Geographers 67: 384-96.

WEST, R. 1948. Cultural geography of the modern Tarascan area. Washington (DC): Smithsonian Institution. Institute of Social Anthropology publication 7.

WITTFOGEL, K. 1957. Oriental despotism. New Haven (CT): Yale University Press.

WRIGHT, H.T. (1984). Prostate political formations, in T. Earle (ed.), On the evolution of complex societies: essays in honor of Harry Hoijer: 41-77. Malibu (CA): Undena Publications.