
Rio Abajo Family Practice, Los Lunas, New Mexico
Chapter 12 of The Prehistoric Pueblo World, by Katherine Spielmann, addresses a very large area including the section of the Rio Grande valley known as the Rio Abajo (roughly the Albuquerque area and further south) and the area of pueblo settlement further east toward the Great Plains. There has been very little research on the Pueblo III period in this area, which reached its heyday somewhat later, and Spielmann notes that she herself is actually a specialist in the later periods but is writing this chapter anyway because there are so few archaeologists with knowledge of the area available.
One result of the lack of attention to this area during this period is that dating of sites is very rough and based mostly on pottery types. This is the case in many other regions, of course, but it is particularly troublesome here because of the limited nature of the data in general. Given that developments in better-dated areas seem to have often occurred very quickly and in very small areas, it is difficult to make many conclusions about overall patterns in a large area without many precise dates.
Spielmann notes these difficulties but does her best to make sense of the data that is available. The main trends here, as elsewhere, during the Pueblo III period involve aggregation and abandonment. While there is a general temporal sequence to these events, with pithouse sites being supplemented as aggregation increases by sites of jacal, adobe, and sometimes masonry, with the end state being either total aggregation or total abandonment, without better chronological control it is difficult to see what exactly is going on in each local area and how the developments in different areas relate to each other. In most areas there seems to be a period of architectural diversity preceding the period of most notable aggregation, but it is impossible to tell how many of these different types of sites (pithouse, jacal, adobe, masonry) are actually contemporaneous and how many are replacing each other as populations aggregate.

Bridge over the Rio Grande at Los Lunas, New Mexico
Spielmann condenses the trends discernible from the data into a few hypotheses about overall trends:
- There are a lot of similar changes between AD 1200 and 1300, particularly in the eastern border areas. These include a period of diverse architecture from 1200 to 1250 and increasing aggregation resulting in the whole population being concentrated in large pueblos by 1300. These pueblos are often composed of rectangular roomblocks surrounding a central plaze, a form that persists in these areas throughout the fourteenth century. This type of community layout is typical of other parts of the southwest during this same period as well, and its prevalence seems to increase over time.
- While the time period covered by this book is really supposed to end around AD 1350, there is a second period of aggregation in the eastern border areas during the 1400s that bears mentioning. The furthest-east areas, those closest to the Great Plains, are abandoned completely by 1400, and there are some tantalizing hints that the inhabitants may have shifted to a lifestyle based on mobility and buffalo hunting. In the remaining areas, the aggregated pueblos of the Pueblo III era further consolidate into a few larger pueblos.
- Aggregation began considerably earlier in the Rio Abajo area proper, with the period of diverse architecture taking place during Pueblo II rather than Pueblo III. However, it is possible that extensive aggregation here was actually simultaneous with that in the eastern border areas; the lack of precision in dating makes it difficult to tell how rapidly aggregation took place. The resulting pueblos certainly look similar architecturally in the two regions.
These developments, to the extent that they can be identified at all, are puzzling, and Spielmann admits that she doesn’t have any solid answers. She reviews several models that have been proposed to explain aggregation in general, including warfare, proximity to resources, competitive emulation, and adaptation to environmental change. She finds most of these unpersuasive or inapplicable to this region, but has the most sympathy to a combination of adaptation to a changing environment and the effects of traditional patterns of land-use and ownership rights (a model most closely associated with the work of Michael Adler). She identifies some tentative correlations between periods of ow rainfall and periods of aggregation, and also notes that at least in some areas the locations of aggregated sites are more favorable for agriculture than the locations of many earlier dispersed sites. The data is, as always, fuzzy, but many of the correlations she notes are indeed suggestive. Her proposals for the role of land-use rights are less convincing, but certainly plausible. They involve patterns of settlement within the better agricultural areas noted above and mostly involve the locations of aggregated communities atop earlier sites and the movement into some areas of groups who may have previously used those areas seasonally.

How to Get to Isleta Pueblo
Overall, the patterns identified here are tentative but intriguing. The eastern border areas in particular seem to show aggregation remarkably late compared to other regions, and while the beginnings of aggregation seem to have been earlier in the Rio Abajo itself, it’s possible that the really substantial movement of population into aggregated pueblos was rather late there too. There is also evidence for considerable immigration into many of these areas toward the end of the Pueblo III period, after a notable lack of such evidence earlier, which suggests some connections to developments elsewhere. The nature of those connections, however, as well as the meaning of developments during this period for the better-known events of later periods, will have to await further, and hopefully more detailed, study.

Warning Sign at Rio Grande Bridge, Los Lunas, New Mexico
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