Lithic resources as a proxy for the social use of territory among hunter-gatherers of Central Chile

This paper presents the results of a study of the composition of lithic raw materials from the contexts of archaeological sites of hunter-gatherers of Central Chile (latitudes 33° to 34.5° S) between 5000 to 1000 years BP. This territory is characterized by a wide distribution of certain coarse and medium-grained lithic raw materials (andesite, basalt and granite), preferably used in low formatted tools, and the specific location of those of fine grain (obsidian and siliceous rocks), suitable for bifacial reduction, only in some localities. In this analysis, 22 sites have been included, each of which presents different proportions of these raw materials in their context, a set that, when analysed in terms of the diversity of each case, generated clear spatial groupings which were ratified by means of a principle component analysis. These groupings of sites are located in direct association with the lithic landscape of different localities within the region, although we propose that the simple cost-benefit explanation would not account for their formation. According to the authors, these groups would be marked by behaviours that can only result from social restrictions on access to certain sources of these raw materials, especially considering that the distances between their location and the position of the different sources in several cases is not too large to be considered a factor in itself. These restrictions could be interpreted as the existence of socially different groups within the study area, a question that is compared with ethnographic data currently available on the size of the territories of different groups of hunter-gatherers and their annual mobility ranges.


Introduction
The concept of territory as it applies to hunter-gatherer groups has been a constant in anthropological and archaeological discussions. While this concept has probably been used since these fields first appeared, it was not until the 1970s that a systematic set of ideas emerged.
Situated within the cultural ecology current that characterized anthropology and archaeology at the time, Dyson-Hudson and Smith (1978) conducted one of the first modern syntheses of the concept, proposing that a territory corresponds to the area that is considered to belong to a certain group and has a perimeter that is defended, through violent repulsion or by the implementation of ways of communicating that ownership. According to the model developed by those authors, this defensive behaviour would favour a group or certain individuals in terms of costs and benefits. This idea was certainly taken up by processual and neo-evolutionary archaeology as one element in understanding how hunter-gatherers used a space (e.g., Binford 1979: 260;Kelly 2013: 77-113).
At the core of this proposal is the notion that the territory corresponds to an area, meaning a delimited portion of a continuous physical space, that can even be described by a mathematical function (e.g., Freeman & Anderies 2015). However, even before Dyson-Hudson and Smith (1978) put forward their proposal, other scholars had pointed out that, for hunter-gatherers, it was not the space by itself that had to be defended. In a comparative study of primates, carnivores, and human hunter-gatherers, from an evolutionary lens, King (1976) concluded that hunter-gatherer groups placed more emphasis on control over resources than on the exclusive occupation of a given portion of space. Along the same line, Ingold (1986) proposed a distinction between territorial behaviour and tenure, the claiming of an exclusive right of use of certain places and spaces, in which hunter-gatherer groups took a one-dimensional approach, meaning they concentrated on controlling places where certain resources existed, rather than a two-dimensional conception, i.e., involving an entire area. This opens up the possibility that a single continuous portion of space could have been used by different groups, each of which claimed certain resource sources.
This last perspective has been used previously (Cornejo & Sanhueza 2011) to discuss the existence of hunter-gatherer groups in the Andes of Central Chile that comprised differentiated social units. In addition to other characteristics proper to their habitus (Bourdieu 1977), these groups were differentiated according to their appropriation of lithic resources, establishing specific differences in the access that each of them had to certain raw materials, namely obsidian and siliceous rocks. In this article, we intend to expand this perspective to the entire territory of Central Chile (Figure 1), using access to lithic raw material as an indicator of the social differences that would have existed among hunter-gatherer populations that lived in this area between 5000 and 1000 BP.

Study area
Central Chile, situated between 33° and 34.5° S latitude, is a narrow territory that stretches hardly more than 120 km east to west, from the Andes Mountains to the Pacific coast. Palaeoclimatic studies conducted here (Villa-Martinez et al. 2003; indicate that beginning around 5000 BP, encompassing the period of our study, Holocene conditions were established that are similar to those found today. These conditions are characterized by a temperate climate determined by the latitude, a marked maritime influence, and an intense altitude gradient, which has led to the formation of five distinct geographical features: the Andes Mountains, the Central Valley, the Coastal Range, and the coastline itself. In the northern part of the Central Valley lies yet another special territory called the Cordón de Chacabuco, a low-lying chain of mountains that runs between the Andes and the Coastal Range. While not very extensive, it is of great interest here. Within this region, hunter-gatherer studies have focused on the mountains of the Andes (Cornejo et al. 2000;2011;Cornejo & Simonetti 1993;1997;Galarce & Peralta 2003;Planella et al. 2005) and on the Cordón de Chacabuco (Cornejo & Saavedra 2017;Hermosilla 1994;Hermosilla et al. 1995;Reyes & Contreras 2017;Stehberg & Pinto 1980;). The other three main geographic features of the region present disparate information about the presence of hunter-gatherers. The Central Valley has been extensively surveyed 2012;Sanhueza et al. 2007), and does not present records of hunter-gatherers, while the coast and its mountain range do present some evidence of these populations, although studies have been very limited and little to no advances have been made in the past 25 years (Falabella & Planella 1991;Gajardo Tobar 1958;Hermosilla & Ramírez 1985;Jerardino et al. 1992;Ramírez et al. 1991). The available information tells us that the hunter-gatherer way of life in Central Chile stretches back close to 13,000 years and lasted until the end of the 19th century (Cornejo 2010;Cornejo et al. 1998). Most of this sequence is known from a small number of relatively isolated sites. However, for 5000 BP onward, a body of information has been developed that has enabled researchers to propose a series of hypotheses about the historic, social, and technological development of this way of life (Cornejo & Galarce 2010;Cornejo & Saavedra 2017;2011;Cornejo & Simonetti 1997). One of the most interesting aspects in this scenario is the coexistence of hunter-gatherer groups with more sedentary horticulturalist groups with well-developed ceramic traditions and a growing degree of economic dependence on agricultural crops. Furthermore, for the Andes Mountains, and the Maipo River basin specifically, researchers have proposed that two socially distinct groups existed that differed in the shape of their camps, in their relations with horticulturists, and in their use of raw materials (Cornejo & Sanhueza 2011). This proposal has been very helpful for understanding how these populations defined their territory, based on access to different lithic raw materials found in the area.

Availability of lithic raw materials
In the lithic landscape of Central Chile, certain raw materials are widely distributed, while others are found only in very specific places. Given that, the geology has been intensely influenced by the formation of the Andes Mountains, the most commonly found rocks are andesites, basalts, and granite. These include a variety of medium and coarse-grained raw materials that present in different ways, as layers or rounded stones of tectonic, alluvial, or volcanic origin. These rocks are hardly suitable for complex stone reduction processes such as bifacial knapping, but they are very suitable for producing relatively simple tools for scraping, flatting out, and crushing. Additionally, a series of located geological events has produced finegrained rocks, especially siliceous rocks and obsidian, with predictable fracturing planes that are especially suited to bifacial reduction, but also produce very useful live edges. These sources are only found in some specific places.
Within this scenario, the alluvial basin of the Central Valley offers a lithic landscape composed primarily of medium and coarse-grained rocks, while fine-grained rocks, most suitable for bifacial reduction, are notably absent. However, as mentioned above, for the sector of the Central Valley studied herein there are no records of hunter-gatherers; the first populations to appear there were semi-sedentary horticulturists, around 1800 BP. These groups would have had to devise ways of accessing sources of quartz, siliceous rocks and obsidian, which they used to make more elaborate bifacial tools, especially projectile points.
Within this "lithic mega-landscape," the rocks of greatest interest are those that were highly valued by hunter-gatherer groups for their stone industries, and these are found only in very localized spots. Using the frequency with which these rocks appear in archaeological contexts, we were able to map possible territories, differentiated by access to these resources.
Obviously, obsidian offers the best kind of information for this approach, as there is a wellproven methodology to determine the precise source of specimens of that stone found at each site. In previous studies (Cortegoso et al. 2014;Durán et al. 2004;Sanhueza et al. in press) it was identified, rather precisely, that the sources of obsidian are located in the southern part of our region of interest, exclusively in the high Andes, with two very close yet quite distinct sources identified: Arrollo Paramillos and Laguna del Diamante (Figure 1), about 150 km south of our area of study in Arroyo Las Cargas. Thus, obsidian was the most localized of the raw materials that comprise the lithic landscape of Central Chile.
Sources of siliceous rocks, for their part, are present in all geographic features except for the above-mentioned Central Valley, although each source presents different features. Thanks to its geological history, the Cordón de Chacabuco has abundant siliceous rocks available, with more than 30 sources identified to date (Figure 1), most of them microcrystalline hydrothermal varieties and silicified volcanic rocks (Aguilera 2012;Castelleti & García 2007). This means that the Cordón de Chacabuco is, in principle, the locality with the most widely available siliceous rock sources, several of which also contain evidence of extraction and processing. For its part, the Andean Maipo Valley has been extensively surveyed, yet to date only two sources of siliceous rocks have been recorded (Cornejo & Sanhueza 2011;Ibacache & Cantarrutti 2007), both hydrothermal, located on the northern slopes of the Maipo River basin, and classified as provisioning and processing sites ( Figure 1). Lastly, on the coast and in its mountain range, as mentioned, archaeological studies have been few, with no reports of specific siliceous rock sources that were exploited in the past. However, both of these areas present abundant geological information about the presence of quartz in veins or seams of different kinds of rocks (Godoy 1994;Parada 1992). These are widely distributed in the area and, as we shall see below, were indeed used by hunter-gatherers. Furthermore, at least one sector of the Coastal Range has been identified (Nasi & Thiele 1982) in which siliceous rocks are likely present, owing to the geology ( Figure 1).

Lithic raw materials and territory
Although, archaeological studies of hunter-gatherer contexts have been uneven in the different geographical features of Central Chile, it is still possible to construct a scenario that addresses the problem we have outlined here for the Andes Mountains, the Cordón de Chacabuco, and the Pacific coast. To do so, our study focused on the by-products of reduction processes and not on manufactured tools, especially bifacial ones, which can be carried over long distances, and as such are a better indicator of exchange and interaction than of territoriality. The by-products of reduction, in comparison, offer much more direct information about the activities carried out at each site, and would have depended upon the raw material that each group possessed. Additionally, by-products of reduction are much more frequently found in archaeological contexts and thus enable us to include settlements with a low density of remains.
For this task, we have used a simplified classification system for the raw materials recorded, focusing on obsidian, siliceous rocks, and quartz. In order to determine the relative importance of each of these high-quality rocks, we have also included the category of medium and coarse-grained rocks (MCG rocks), which encompasses a wide variety of andesites, basalts, and granites. This classification, and the proportions of by-products found for each category at each site, can be observed in Table 1. Other raw materials that do not fall under this classification appear in different contexts, but because they are ultra-localized or found in very low proportions, we have not included them in this analysis. to these resources. We can measure these two variables using the diversity index (H) developed by Shannon and Weaver (1949: 51), which is designed to measure this indicator in terms of richness and evenness and will enable us to assess the overall distribution of raw materials at the sites studied. Richness represents the quantity of different types of raw materials that are present at each site, while evenness reflects the proportion of each raw material found at each site. The value that this index H attains for each site is shown in Table 1, along with the percentage that this value represents in the hypothetical case in which all raw materials are present in all sites in the same proportion, or Hα, whose value is calculated in the following way: Hα = log e (N) in which N corresponds to the total quantity of categories among which a variable is distributed, in this case the quantity of types of raw materials. This value in our case is 1.386.
Thus, we observe ( Figure 2, Table 1) that the sites fall into certain relevant sets or groups. In the lower part of the distribution there is a group of three sites with low diversity of raw materials; they do not reach values higher than 15% of Hα, and one only reaches 4.8% owing to its high concentration of siliceous rocks (98.8%). The next least diverse group yields a diversity measure 13.1% higher than the previous one. The other end of the distribution, with values greater than 65% of Hα, contains a set of seven sites that present high diversity of raw materials, with values 6.4% higher than the second most diverse grouping. Most of the sites, however, fall into the centre of the distribution. The majority of these present values between 43 and 49% of Hα, spaced relatively evenly apart, with differences of no more than 3% between each. The remaining three sites are relatively isolated, with values ranging from 26 to 37% of Hα. The two sets of sites found at the two extremes of the distribution both present clear spatial associations, one concentrated in the Cordón de Chacabuco and the other in the southern part of the Andes Mountains (Figure 1). This spatial distribution can be observed in greater detail by a principal component analysis, with Factors 1 and 2 explaining 98.49% of the variation of the entire set ( Figure 3). This analysis clearly show that the distribution of sites is determined by the relative weighting of the different raw materials and their location in space, forming spatially differentiated groups (Figure 4). Group 1 encompasses the three sites we examined on the lowest range of the Hα percentage scale (Figure 2). They are located in the Cordón de Chacabuco and are grouped very close together by the high importance of siliceous rocks in their archaeological contexts. Nearby is the Carmen Alto 6 site, in the same locality, although the presence of 10.8% of quartz by-products shifts this site towards the quadrant where that raw material is important. Next, grouped together in the quadrant where obsidian is prevalent are 11 sites in which this raw material dominates the context, several of which fall into the higher range of Hα % distribution ( Figure 2). All 11 sites are found in the southern part of the Andean sector, forming Group 2. This group is less compact than Group 1, with the distribution extending towards the quadrant where siliceous rocks are the protagonist, as some of this raw material begins to appear in these contexts (Table 1); but they maintain their distance from Group 1. The rest of the Andean sites, all located in the northern zone, are spread around the quadrant with a preponderance of siliceous rocks. We have identified these as Group 3. In some sites (La Paloma and Condominio 1), the presence of waste from MCG rocks is also significant, although insufficient to justify a separate group. Evidently, this group is less homogeneous than the two previous ones.
Lastly, in the upper section of the dispersion, there are two sites whose only common feature is their high frequency of MCG rocks, although at LEP-C, quartz is the leading fine- At the LEP-C site, located on the coast, the high frequency of quartz makes it virtually the only fine-grained raw material in its context (Table 1). A review of the collection from an excavation conducted three decades ago (Falabella & Planella 1991) confirmed that all of the quartz present is very characteristic, having a whitish, semi-transparent colour, amorphous appearance, and structure that tends to produce more angular rather than conchoidal fractures, making it less suitable for bifacial reduction than other raw materials discussed herein. The preponderance of quartz found at LEP-C is consistent with information published about another known coastal site, Punta Curaumilla 1, where, although in initial occupations quartz is not significant, at later levels, contemporary to the sites studied herein, quartz accounts for up to 91% of waste material found in the context (Ramírez et al. 1991). This leads us to define a Group 4, on the coast.
For now, the Cuchipuy site stands alone, although more in-depth investigations in the area may identify other sites with a similar lithic composition. In fact, some information from at least one other archaeological site in the southern part of that area (Tagle & del Río 2006) indicates it may share certain characteristics with Cuchipuy, but much more detailed studies of those findings would need to be conducted to include that site here. Based on their location and the configuration of raw materials found within them, these groups of archaeological sites are largely consistent with the lithic landscape described above (Figure 4). The sites of Group 1, in which siliceous rocks predominate, are located near the abundant sources of this raw material in the Cordón de Chacabuco. The sites of Group 2, where obsidian predominates, are near the sources of that raw material in the Andean volcanic zone. Group 3, for its part, is in a zone where at least two sources of siliceous rocks have been identified, and despite it being a mountainous territory, like that of Group 2, there are no sources of obsidian nearby. Lastly, Group 4, for which we have used our own data for the LEP-C site and published data for the Punta Curaumilla 1 site (Ramírez et al. 1991), is in the coastal region, which, despite the lack of archaeologically-identified sources where this rock was extracted, is known geologically to contain it (Godoy 1994;Parada 1992). Thus, it can be affirmed that in Central Chile, the contexts associated with the use of lithic raw materials is directly associated with the lithic landscape present. This could be interpreted as the obvious result of a strategy of economic maximization, in which the inhabitants use the materials that were most abundant in each place, to avoid having to transport cores, bifaces, or other performs. Nevertheless, some aspects of the distribution of these raw materials in Central Chile challenge this simple economic interpretation and points rather to the existence of groups with socially-differentiated access to existing lithic resources.
First of all, as some of us have argued previously (Cornejo & Sanhueza 2011), in the Andean basin of the Maipo River, it is possible to identify two territories occupied by two different hunter-gatherer communities, corresponding approximately to Groups 2 and 3 defined herein, each with different access to sources of raw lithic materials. In that study (Cornejo & Sanhueza 2011: 495-497) we indicated that the distance to sources of obsidian, the only raw material with clearly-defined sources which are extremely localized, while it explains 59% of the difference in obsidian frequency at the sites (r 2 = 0.59), also leaves a percentage variation in the quantity of obsidian larger than what can be explained by distance alone. In this analysis, where we consider a much broader territory, and where at first glance it also seems evident that the most distant sites contain less obsidian, we see that the regression between distance and percentage of obsidian only leads to a small increase in the dependent variable (% of obsidian) as explained by the independent variable (distance), from 59% to 63% (r 2 = 0.63).
Moreover, there is an area in Andean basin of the Maipo River, the Yeso River ( Figure 5), where the difference among sites classed as Group 2, with a predominance of obsidian, and those of Group 3, with much more diverse raw materials, is in practice impossible to explain simply on the basis of distance from obsidian sources alone. This area includes three sites, Las Cortaderas 2, Las Cortaderas 3 on the southern bank of the river, and Las Morrenas 1 on the northern edge, that present dramatically different proportions of obsidian. While at Las Morrenas 1 the percentage of obsidian is just 4.5%, in Las Cortaderas 3, just 3.3 km away, on the other side of the river, that percentage is 44.0%, and at Las Cortaderas 2, some 5.4 km from Las Morrenas 1, also on the southern bank, the percentage is 27.4 % ( Table 1). In other words, the access to obsidian among contemporary hunter-gatherer groups that occupied sites just across the river from each other varied by a factor of 5-10:1. We can therefore argue that the percentage of obsidian is not related strictly to distance from the sources of these raw materials, which is practically the same; instead, it is more likely that the difference arises from socially differentiated access to those sources (Cornejo & Sanhueza 2011).
Albeit to a different degree, we also contend that the scenario among Group 4 coastal sites also clearly expresses the presence of socially differentiated access to certain lithic resources. At the LEP-C site, for example, the presence of other fine-grained, non-quartz rocks is very low, amounting to just 1.1% for obsidian and 3.2 % for siliceous rocks (Table 1), and similar figures have been reported for the Punta Curaumilla 1 site (Ramírez et al. 1991). However, quartz, which is part of the coastal lithic landscape, is much less suitable for bifacial reduction than siliceous rocks or obsidian. The very limited access to obsidian can be explained by the 213 km distance over which group members would have had to transport that rock from its closest source at Laguna del Diamante (Figure 2). But the same reasoning does not seem sufficient to explain the low quantity of siliceous rock by-products at the site, when abundant sources of that raw material can be found just over 75 km away in the Cordón de Chacabuco sector, and perhaps even closer, as geological information (Nasi & Thiele 1982) attests to the presence of this kind of raw material just 55 km away in the coastal range itself (Figure 2).

Figure 5. Yeso River locality
Additionally, it is worth considering whether the total size of the space within which the sites studied are found, and the distances between each of the sites, could be pivotal in defining these groups, making this essentially a matter of their mobility.
As there is no archaeological frame of reference that could help with this definition, or none that would not be tautological, we turned to existing ethnographic records. Obviously, this kind of analogy has serious limitations, particularly as there are no ethnographic records for groups occupying a region ecologically similar to the one in question, the temperate forests of our area, and because from a more general perspective, most ethnographic studies focus on groups that had already come into some kind of contact with industrialized societies.
The set of ethnographic data published by Binford (2001 : Table 5.01) offers us a precise comparison for assessing annual mobility ranges of a large number of effectively mobile huntergatherer groups. Analysis of that information (Table 2) allows us to observe that, while there is high diversity within a minimum of 3 km and a maximum of 570 km yearly ( = 171 km σ =144), 49.8% of the groups studied moved more than 120 km per year, and in fact, 36.6% covered more than 200 km annually. Thus, when we consider the area encompassed by the dispersed sites studied here, where the maximum distance along the optimal route between the most distant points is just 192 km, we can conclude it is very likely that a single group could have covered the entire territory under study here. It would thus be surprising if, when traveling  Table 5.01), we observe that the size of the territory occupied by different mobile hunter-gatherer groups (Table 3) is, as one would expect from the mobility data, very diverse, with a minimum area of 80 km 2 and a maximum of 660,000 km 2 ( = 42.260 km 2 σ =91.948). However, 65.1% of Binford's cases occupied a territory less than or equal to that covered by our sites (17,133 km 2 ) and a major percentage (48.9%) had territories that were half the size or less than the territory covered by our sites. This information, which shows that there are enough examples of hunter-gatherer groups that occupied territories much smaller than the space available in Central Chile, makes it plausible that four different hunter-gatherer groups existed within the territory studied at the same time.

Discussion and Conclusions
According to the analyses conducted, the proportion of lithic raw materials, recorded as by-products of reduction at hunter-gatherer archaeological sites in Central Chile, allows us to define four groups, each associated with the lithic landscapes of the different regions in which they are situated, especially in regard to the fine-grained raw materials most suitable for bifacial reduction. These groups could not have resulted from a simple cost-benefit analysis by a single group that moved around the entire territory, accessing the raw materials from sources available in the respective lithic landscapes. In this way, it can be stated that the access to different sources of raw lithic material was subject to some restrictions, which suggests the existence of groups with socially differential access to certain sources. For the Andean area, some of us have argued previously (Cornejo & Sanhueza 2011) that the differential access to raw materials such as siliceous rocks and obsidian; the differential use of different types of camps; and, among later hunter-gatherers, different forms of interaction with contemporary semi-sedentary horticultural groups, all point to the presence of two well-defined, socially differentiated communities. These two huntergatherer communities correspond to what we have named Groups 2 and 3 here.
Furthermore, the sites that comprise what we have called Group 1, are all located in the Cordón de Chacabuco, and present not only a special concentration of siliceous rocks, which is abundant in the locality, but also other features that could reinforce their identification as a socially distinct group. All of the sites studied, and most of those recognized in our field surveys (Cornejo & Saavedra 2017), are open-air sites associated with one or more boulders with multiple mortars perforated into the rock, called locally as piedras tacitas ("cup stones"). While we do not yet know precisely what their creators crushed within those mortars (Belmar & Carrasco 2017;Planella & McRostie 2017;Planella et al. 2018), their frequent occurrence in the Cordón de Chacabuco indicates that the place offered some kind of resource that was of special interest to its ancient inhabitants.
Beyond those features, however, we must also consider the location of sites with piedras tacitas (Cornejo & Saavedra 2017;Planella et al. 2018), which reveals particular features not found among the other groups defined herein. First of all, each site has several mortars, which means that the activities carried out there could have been collective. Second, most sites are positioned so that the tasks carried out there would have been very visible to others in the surrounding area, which implies that those activities would have been public. These two features, collective work and public exposure, are not present at sites in any other group defined here and, we believe, when combined with the easy access to sources of siliceous rocks in the locality, points to the existence of a third group in the area of the Cordón de Chacabuco with a habitus (Bourdieu 1977) that is clearly distinct from that of other hunter-gatherer groups in the region.
Lastly, the scenario on the coast also seems to display some particularities. Despite the evidently small sample size, the few sites studied also represent a group distinct from those already defined in the interior. This is especially highlighted by the almost complete absence of siliceous rocks and obsidian by-products, indicating that the groups living in this area had very restricted access to the sources of these rocks, and could only work with the inferior-quality quartz that was available on the coast. The evidence supplied by the lithic context is reinforced by an analysis of δ 15 O isotopes of four individuals buried at the LEP-C site (Falabella & Sanhueza 2019), which showed that they lived on the coast for most of the year.
Thus, privileged access to certain resources would be representative of social differences among the hunter-gatherer groups of Central Chile, and, as we have mentioned, is also linked to other aspects of the social lives of these groups. As we have seen, the ethnographic data on mobility range and territory size (Binford 2001: Table 5.01) demonstrate that the situation described here is compatible with those observed by ethnographers in many hunter-gatherer groups.
Still, this social configuration of the space does not mean that territories were completely hermetic; rather, it indicates that this practice occurred as part of what Ingold (1986) called a one-dimensional territorial strategy, in which control of certain resource sources does not imply control of a two-dimensional space, as defined by a perimeter. A clear example of this is the circulation of small amounts of obsidian from the only available sources, within the territory of Group 2 sites, to distant sites such as LEP-C and Carmen Alto 6 (Table 1), which means people moved around and transported this rock outside of the territory where it originated. The same can be said for the small percentage of siliceous rocks that came to the coast, very probably from sources in the Cordón de Chacabuco. This definition of territory is especially evident in the late period in the space occupied by Groups 2 and 3, where they closely co-existed, embedded among semi-sedentary horticultural groups, with some settlements less than a kilometre from each other 2011). These semi-sedentary horticulturalists would also have had access, albeit to a lesser degree, to the fine-grained raw materials used by the hunter-gatherers. Finally, it is evident that the space occupied by the four distinct groups defined here does not truly represent the entire geographic extension of the territory in which they ranged; it simply represents the degree of knowledge we have today about hunter-gatherer occupations in Central Chile. For Group 2, as mentioned (Cornejo & Sanhueza 2011), the information available about the eastern Andean watershed (Durán et al. 2006;Lagiglia 1997;Lagiglia et al. 1994;Neme et al. 2016) just over the Andes from the space where this group is situated, indicates that its area of mobility would have included that basin. And one could imagine that Group 1's mobility circuits extended to the semi-arid north, where a north-south mobility pattern has already been proposed in which the availability of siliceous rocks sources was a defining element (Galarce 2014: 113).