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Errett Hargrove Callahan Jr. was a standout American pioneer in experimental archaeology, lithic technology, and replicative experimental studies. Errett, son of Errett Callahan, Sr. and Mary Ingraham Callahan, was born on December 17th, 1937 in Lynchburg, Virginia, where he lived until his death on May 29th, 2019. He leaves his son Tim, daughter Melody, and three grandchildren, Chris, Megan, and Ryan.

Describing cultural change and variability and inferring sociocultural dynamics about past people and communities may be among archaeology’s main goals as a field of practice. In this regard, the concept of skill has proved its usefulness to, time and again, expand the breath of archaeologists and lithic technologists’ analyses. It covers a wide range of applications, from apprenticeship, cognition, paleo-sociology, spatial organization. It is one of the main causes for material culture variability, up there with raw material constraints, design, technological organization or cultural norms. Yet, while skill has certainly been the focus of some research in the last decades, it remains quite peripheral, when considering how central the concept should be to technological inquiries. Whatever the reasons may be, this book, edited by Laurent Klaric and fully bilingual (French and English), aims at changing that, and argues for skill to become a central concern in lithic technology. Its chapters do so strongly and the end-result is a book that should become a reference for lithic technologists, whatever their research interests or schools of thought may be.

This paper is divided into three sections. The first section describes the historiographic evolution of the study of prehistoric lithic raw materials in the Basque Crossroads (in the north of the Iberian Peninsula) during the last three decades. The second section explains the currently available information about geological outcrops of flint in the eastern end of the Cantabrian Mountain range (the Basque-Cantabrian Basin), the upper Ebro valley and both sides of the western Pyrenees, in the central part of the northern Iberian Peninsula, as that was the main raw material used by hunter-gatherer groups in the Middle and Upper Palaeolithic. Finally, the last section describes the way in which progress in both aspects of research have enabled the introduction of new concepts and perspectives in the reconstruction of the social and economic dynamics of Palaeolithic hunter-gatherers. This has given rise to an innovative methodology that is able to address and solve important issues, particularly regarding mobility and territoriality patterns of those human groups, allowing the proposal of mobility and territoriality models that, while they will not match exactly the systems used by Upper Palaeolithic communities, represent significant progress in understanding the social and economic dynamics of hunter-gatherer groups. This research was partially supported by the project HAR2017-82483-C3-1-P financed by the Spanish Ministry of Science and the Consolidated Research Group in Prehistory of the Basque Country University (IT-1223-19). M. Garcia-Rojas, E. Dominguez-Ballesteros, A.Prieto, A. Calvo, A. Sanchez and A. Arrizabalaga are part of this project and they are members of the research group. E. Dominguez-Ballesteros, A. Prieto and A. Calvo are funded by the Education Department of the Government of the Basque Country through a postdoctoral fellowship (POS_2019_1_0004, POS_2018_1_0021 and POS_2019_1_001

This article presents data on chipped stone techno-economic patterns of nomadic hunters-gatherers at a quarry source area in the Temiscouata region (Quebec, Canada) during the Middle late Woodland (1500-1000 BP) and the Late Woodland (1000-450 BP) and also the early historic period (450-250 BP). Located in the hinterland of the Bas-Saint-Laurent, in the upper St-John river drainage, the Temiscouata region is rich of many common natural resources, but also by the presence of an important chert outcrop. The Touladi chert is present in two main quarries and is also found in pebbles forms scattered in the vicinity of the surrounding lakes and rivers. We applied a technological analysis, from the technological approach in the French tradition, on five lithic collections in the objectives to reconstruct the chaine operatoires and their economic management patterns (techno-economy). This methodology was first applied on the local chert material and afterward on the exotic chipped stone artifacts in order to study the patterns that prevailed while hunters-gatherers were outside the quarries zone and also to understand the influence of the outcrops in the economics patterns. The most prominent artifacts found is of course the numerous flakes which can be derive from three different chaines operatoires: the bifacial process, the multidirectional (ad hoc) core reduction and the use of pieces esquillees. The production of bifacial tools is the most important process in Temiscouata lithic industries and is the one who produce most of the flakes found on prehistoric settlements. Core reduction sequence is unstandardized and is responsible for just a small part of the flakes product. The pieces esquillees process is only found on two sites and the flakes are generated unintentionally during the used of these artifacts. The tools assemblage is first characterized by the bifacial tools which are mostly manufactured on raw tabular blocks of chert. As for the flake tools, they are mostly represented by informal (ad hoc) tool (retouched and used flakes), endscrapers and pieces esquillees. Techno-economics patterns on Touladi chert have demonstrated that most of the flake tools were made on flake blanks derived from the bifacial process, mostly from the early and middle stages of this chaine operatoire. Bifacial process was also fractioned in time and space and we found that bifacial blanks and preforms were carried throughout the territory to be used as “cores”. The two other productions are quite secondary in respect of the small amount of tools manufactured and they are far less mobile than the first one.Exotic materials show similar and different patterns than those observed on local chert. The bifacial process is still the dominant one and the most prominent way to make flake tools when the quarries are remote. Even then, they still use mostly flakes derived from early and intermediate stages of reduction. Core reduction is interesting because it shows different techno-economic patterns. Reduction sequences are more formal or at least more efficient than those observed on Touladi chert. For example, a small discoid core demonstrate a more complex reduction method which allows a greater ratio of flakes production compared to the multidirectional core processes used in the Temiscouta region. This is partly a consequence of the exotic raw materials used for cores, which is in the form of small pebbles. But it is also probably an adaptation of the core technology in the purpose of making it more efficient and more productive when knappers were away from lithic sources. However, the use of core technologies was probably a second choice, mostly adopted when the raw material did not allow the manufacture of bifacial tools. Bifaces used as cores seem to have prevailed when it was possible to do so. As for the pieces esquillees, they do not seem to have played an important part in tool fabrication in context of raw material scarcity. Another interesting aspect of tools manufacturing with exotic materials is the behavior of carrying flake blanks. Every site shows numerous flake blanks, imported and discarded unused, a behavior which reveals that the prehistoric groups were carrying more flakes than their real needs. Conversely of the curated bifacial tools, which were discarded in quarry zone only if their economic threshold was reach (fractures, size too small, inadequate morphology, knapping accidents, etc.), flake tools and flake blanks were mostly discarded at workshop sites in a gearing up strategy. The results demonstrate also that all the flake tools were not managed in the same ways. Endscrappers, unlike the other flake tools, show some evidences of curation, but not as important as bifacial tools. Since they are discarded less quickly than the ad hoc tool and pieces esquillees, this behavior explain probably why the imported endscrappers are found in greater amount at the Temiscouata sites. The technological analysis shows empiric evidences that hunter-gatherers of the Temiscouata adopted flexible and simple, yet very efficient, techno-economical strategies. These management schemes, which use bifacial chaine operatoire as the central element of the tool manufacturing, seem well adapted to their way of life based on a generalist, seasonal and flexible subsistence economy. Exotic artifacts, even if they represent a small part of the archaeological record, can reveal important aspects of the organization of past stone tool technologies.

International audience; At the end of the Pleistocene (25,000-15,000 BP), there is a shift to more arid conditions in the Negev and the Sinai corresponding to the Last Glacial Maximum. For the Nile Valley and the Levant, the lowering of the Mediterranean sea level, the expansion of the Sahara and the desiccation of some major eastern African lakes had important consequences on: (1) the general behaviour of the River Nile; (2) the landscape around the Nile Delta; and (3) sand dune mobilisation. Despite this shift to more arid conditions, there is abundant evidence for human occupation in the Egyptian Nile Valley and in the arid zone of the Southern Levant at this time. In addition, contacts between these two regions have sometimes been suggested, mainly by genetic studies, including early ‘Back-to-Africa’ dispersals.This paper focuses on the analysis of six terminal Pleistocene (ca. 25,000-15,000 BP) lithic assemblages from the western Negev Desert dunes in Israel, attributed to the Early and Middle Epipalaeolithic. The analysis relies on the chaîne opératoire approach combined with attribute analysis that enables quantification of typo-technological differences. Results of this analysis allows comparisons with assemblages from the Egyptian Nile Valley analysed in the same way previously. This comparative analysis is then used to discuss hypotheses of potential technical diffusions between these two regions. Current archaeological evidence therefore does not support any contacts between populations between the Levant and the Nile Valley at the end of the Pleistocene.

This paper focuses on current research on early colonisation of the Atlantic coast of South America during the early Holocene. We present advances in the investigation of raw material procurement at the Rincón de los Indios site, located in the eastern part of Uruguay. The technological studies suggest that some aspects of different styles of projectile points are related with environmental adaptation processes, experienced by the first American people in the New World. The occupation of new spaces and new forms of exploitation of resources changes the organisation of lithic technology. The distance to good quality rocks were critical for the opportunities and economic organisation of hunting groups. The study of changes in lithic procurement strategies for projectile points helps us develop a more comprehensive knowledge of this important social adaptation process which occurred during this period. These patterns started to become stabilised in the latter part of the early Holocene across the extended territory and confirm the efficient land occupation associated an intensive hunter-gatherer economies.

Since the 1970’s, the study of lithic prehistoric collections in France has improved through a profound modernisation. Andre Leroi-Gourhan, first interested in traditional and ethnological techniques, decided to consider all remains and traces left by a human group within a prehistoric site as evidence of its activity, thus opening the “palethnological perspective”. He also promoted the principle of “chaine operatoire” (that is, to consider the successive actions and gestures engaged in the transformation of diverse raw materials) a notion which had been formerly introduced by Marcel Mauss. But, it is the experimentalists of stone knapping, Francois Bordes and Jacques Tixier, who made it possible to enrich this notion with its concrete applications. Above all, Tixier, armed with his clear practical understanding of knapped pieces and his pedagogic skills, enriched and stabilized the lithic terminology, and systematized the “technological reading” of lithics, in other words, the reading of the direction and order of the different scars (negatives of previous removals) visible upon the surface of a flake, a core, or a shaped tool, thus allowing one to mentally reconstruct the fabrication of a tool or the reduction of a core. He also introduced the capital distinction between the “method of knapping” (the arrangement and succession of the removals to reach the goal of the chaine operatoire, i.e., a type or a class of blanks or tools), and the “knapping techniques” (that is, the practical mode of detachment, e.g., direct percussion with a hard stone or a wooden billet, pressure with an antler or copper point, etc.). On this basis, in 1980, Tixier together with a few close colleagues from France and Belgium introduced the concepts of economy of raw materials, debitage, and tools, all three concepts being corollaries of the concept of management rules. The notion of intention - which articulates the blank production modalities and the morphology of the blanks obtained and that of the final tools - also appears, which is the basis of the postulate according to which the knapping modalities (effective decisions and actions) are coherent with the morphology of the expected or priority products. It is this postulate, parallel to that of “design theory” taken up by Brian Hayden, which founded, through the consideration of all the lithic remains, the French approach in lithic technology: to perceive - to understand - the intentions of lithic production within a site or collection before classifying and measuring. This principle is then applied to the small (324 pieces, including 30 to 40 tools) lithic collection from the site of Yokomichi (Yamagata Dept., Northeastern Honshu), with blade production but without (i.e., anterior to) bladelet or microblade production; thus datable to approximately 18,000 BP C14 non-calibrated, from regional chronostratigraphical comparisons). At first it appears that two different blade productions co-exist: one of light and straight blades with a small platform remnant detached from slender cores, and the other of larger blades with a thick platform remnant detached from wider cores. Among the retouched tools, it is the few “Sugikubo knives” (straight and pointed backed points) whose blanks correspond to the priority intention of the slender core reduction, a few other tools being retouched on “second choice” blanks (irregular, too thick, etc.). Such a Sugibuko knife, in a similar collection, shows a fracture with a ventral elongated tongue [“languette” in French] that strongly indicates that this type of tools is actually, at least in part, a projectile point. Various observations then suggest that the priority intention of the wide core reduction was to obtain one or a few large pointed blades, which are very difficult to achieve, while its many second choice products and by-products (being too short, having cortex, etc.) could have been used as unretouched knives or resharpened as “Kamiyama burins” (these are indeed blades or flakes modified by a “pseudo” upper plane burin blow from an inverse truncation, very similar to Kostienki knives). A further experiment shows that both blade productions were made by direct percussion with a soft stone, but in different ways: by tangential percussion for the light blades with a small platform, and by direct percussion inside the striking platform for the stronger blades with a thick platform.

Aknashen (autrefois appelé Khatunakh) est un petit village néolithique de la vallée de l’Ararat localisé à 25 km de Erevan (capitale de l’Arménie) et à 5 km au sud-ouest d’Echmiadzin (Vagharshapat). Aknashen est également situé à seulement six kilomètres d’un autre village néolithique qui lui est contemporain : Aratashen, site pour lequel nous avons récemment publié une étude tehnologique du matériel lithique en obsidienne. Des fouilles ont eu lieu chaque année à Aknashen depuis 2004. En ce qui concerne le matériel lithique, ces travaux ont permis de mettre au jour deux chaînes opératoires principales de matériel en obsidienne (matière très abondante dans cette région) : l’une est peu élaborée sur éclats (expedient tools) et l’autre concerne la confection de longues lames régulières selon plusieurs techniques de débitage. Le présent article portera sur l’industrie laminaire de longues lames régulières obtenues par différentes techniques : pression debout à la béquille, pression au levier et percussion indirecte. La ou les chaînes opératoires qui concernent ces artefacts ne peuvent être reconstituées en entier puisque des éléments manquent et nous ne pouvons pas savoir de façon absolue si par exemple les fines lames débitées par pression à la béquille ont été obtenues après le débitage et la réduction progressive de nucléus d’abord taillés par percussion indirecte, puis par pression au levier. Mais même si divers facteurs nous échappent, dont aussi notamment les lieux exacts où s’est déroulé le débitage, même si la présence d’une panoplie de produits de débitage laisse présumer que le tout se soit déployé en tout ou en partie sur le site, une étude attentive de ce matériel a permis de diagnostiquer les techniques utilisées, mais aussi d’observer le grand niveau de savoir-faire des spécialistes qui ont effectués ce travail de pointe. De façon générale, la pression à la béquille, ainsi que la percussion indirecte, sont les deux techniques d’obtention de longues lames les mieux connues, alors que la pression au levier, même si identifiées dans plusieurs cultures du Néolithique à l’Âge du bronze a fait l’objet de peu d’études de ce genre jusqu’ici. Non seulement ce savoir-faire de haut niveau gagne-t-il à être connu d’un point de vue technologique, mais la reconnaissance du débitage par pression au levier, peut justement constituer un marqueur culturel précieux pour en arriver à caractériser des cultures, des échanges et éventuellement des mouvements ou contacts entre populations. Dans le cadre de cet article, les principaux spécimens liés à l’identification de chaque technique seront présentés, décrits et commentés et ce matériel sera replacé dans une perspective plus large pour la compréhension de cette culture et de ses origines, autant d’un point de vue de l’histoire des techniques et des savoir-faire que pour la connaissance des origines de ce Néolithique encore mal connu. Comme ces recherches sont encore relativement jeunes, bien des aspects sont encore à confirmer et ceci fait partie de travaux qui se poursuivront dans les années à venir.

This paper presents an overview of the knapping techniques of the Second Mesolithic and Early Neolithic during the 7th and 6th millennium in Northern France. This period is characterised by the emergence of new armatures - the trapezes - and of new techniques of prismatic blade production that show discontinuation from the preceding technical traditions. Basically, if we admit that the success of these new technical practices is linked to their intrinsic qualities (higher regularity and parallelism of the blanks, control of the gesture and of the impact point as well as higher productivity), this can explain that the investment into the production focuses on the blanks rather than on the processes of retouch. This paper presents the current state of the data regarding the knapping techniques and their distribution. This analysis is based on the technological approach aiming at characterizing the types of production and the techniques of percussion. At the current state of analysis, only indirect percussion (punch) knapping technique is observed in the northern and western part of the area. Nonetheless, a more detailed study is still required in order to better describe distinct, very regular bladelet productions made from small-sized cores (eastern part of France). With respect to the geographical extension of the considered area, it can be stated that technological studies are still indigent. The debitage of L’Essart A seems to correspond to the common thread of the Late Mesolithic types of production by indirect percussion. However, some well-documented areas allow the perception of different types of indirect percussion which involves variants independent from the raw material which become apparent in the knapping procedures. This is the case of the the Retzian which is clearly opposed to the Teviecian through the procedures of systematic core preparation by microfacetting but also through the outstanding stylistic unity of the trapeze types. Debitage on the edge of a flake for the creation of blade surfaces seems for instant restricted to the Tardenoisian in a wider sense which means an area extending from the Paris Basin to Belgium. The chronological dimension is a crucial factor that has to be incorporated into the analysis. With regard to indirect percussion, an expanded chronological framework of the lithic assemblages would permit to understand whether the different variants are synchronous or diachronic. New discoveries gave us a better idea of the beginning of indirect percussion in Paris basin (around 6200 cal BC according to the dating of the grave of Cuiry-les-Chaudardes). The study of this « complex » of trapeze industries encompasses several levels of observation that have to be refined. The phenomenon is considered here globally. But as we have seen, some well defined entities seem to emerge within this complex. These are preliminary results for the moment and an interpretation that makes sense has yet to be made for these different practices. The typological evolution of trapezes and derived triangles has to be incorporated into the results obtained from the technological approach in order to determine whether the stylistic and technological entities can be correlated. The precise intersection between the stylistic entities and the technological variants assumed here has to be demonstrated. It will probably be possible to subdivide this complex in order to better understand its evolution.

The lithic assemblage of Ribeira da Ponte da Pedra site (OIS8-9) was produced, almost exclusively, through the exploitation of good quality quartzite fluvial pebbles with a regular morphology. Quartzite fluvial pebbles are the most common raw material found in the Middle Pleistocene occupation sites in Portugal. Such feature results from the easy availability of these pebbles in the valleys where the great majority of the archaeological sites within this chronology are located, and also because of the quartzite’s physical properties and suitability for knapping. In a techno-typological point of view, its lithic assemblage is characterized by the application of two main reduction sequences that result in abundant worked pebbles, retouched pebbles, cortical and semi-cortical flakes, retouched flakes, a few cores and rare bifacial artefacts. Some artefacts present irregular and variable edge modifications described as ‘atypical’ edge modifications that could edge damage resultant from their utilization. From a strictly technical point of view the assemblage can be described as quite simple, however we can envisage an inherent complexity starting in an accurate selection and exploitation of the quartzite pebbles, whose regular morphology allows a ‘predetermined’ production of regular blanks through simple actions. In order to better understand patterns of raw material selection and technical schemes adopted in the exploitation of the quartzite pebbles we compared a sample of pebbles collected in the same deposits identified in the site (t4 fluvial terrace deposits) with worked pebbles that have 1 or 2 removals that had not altered significantly the original morpho-volumetry of the pebbles. The goal of this comparison was to verify if there was a selection of the fluvial pebbles based on texture and morpho-volumetry and if so, relate such selection with the technical schemes identified by technological study of the assemblage.

Seeing Lithics represents a doctoral thesis submitted to Harvard University by Gilbert Tostevin in 2000. Tostevin is currently a professor of Anthropology at the University of Minnesota and has written extensively on human evolution, lithic technology, Old World archaeology, and Palaeolithic archaeology. These interests can be clearly seen in this book which develops a new theoretical and analytical approach to the study of cultural transmission in the Middle-Upper Palaeolithic transition.

The book is the result of a Brazilian symposium which took place in 2007, entitled Lithic technology in Brazil. Theoretical foundations, problems and research perspectives. The symposium brought together some of the most important lithic studies researchers in Brazil at the time. Each researcher wrote a chapter concerning the aims of the symposium.

Clovis Lithic Technology presents a detailed technological, typological, and spatial analysis and interpretation of the Clovis lithic assemblage from the Gault Site in central Texas. The Gault site itself is a sine qua non of Clovis sites and represents one of the few of such locales that can be identified as a workshop associated with this industry. The technical descriptions, published data, and interpretive detail of this volume make it a welcome addition to the growing body of new technological information on Clovis in general.

Archaeological Concepts, Techniques, and Terminology for American Prehistoric Lithic Technologyby Wm. Jack HranickyAuthorHouse, Bloomington, Indiana, 2013, pp. 611, ISBN 978-1-4817-5173-5

Introduction to Paleoamerican Lithic Technology at the University of Oregon Archaeological Field School.

The industry of metatuff axes and adzes on the western coast of Onega Lake (Eneolithic period, ca. 3500 – 1500 cal. BC) allows assuming some sort of craft specialization. Excavations of a workshop site Fofanovo XIII, conducted in 2010-2011, provided an extremely large assemblage of artefacts (over 350000 finds from just 30 m2, mostly production debitage). An attempt to estimate the output of production within the excavated area is based on experimental data from a series of replication experiments. Mass-analysis with the aid of image recognition software was used to obtain raw data from flakes from excavations and experiments. Statistical evaluation assures that the experimental results can be used as a basement for calculations. According to the proposed estimation, some 500 – 1000 tools could have been produced here, and this can be qualified as an evidence of “mass-production”.

Taphonomy and lithic technology in a highly dynamic environment: The case of the penguin colony of La Pastosa Islet (Rio Negro Province), Patagonia, Argentina This paper presents the first results of taphonomic and technological analyses of the lithic assemblage recovered on La Pastosa Islet, on the coast of Rio Negro province, Patagonia, Argentina. This archaeological record is particular because it has been under a high formational dynamic and is located in an area recently occupied by a colony of Magellan penguins ( Spheniscus magellanicus ). Two samplings of lithic material were made, for which technological, metric and taphonomic variables were registered. La Pastosa is an 8 hectare islet, which is located 768 m. from the continent, and is only attached to it at low tide by a narrow land strip that runs through a marsh. While the absolute age of this island is unknown, we know that from the late Holocene, around 3000 BP, sea level reached current levels (Favier Dubois 2013), and since that time the islet was visited by hunter-gatherers, who buried their dead in the highest part of the island (Favier Dubois et al. 2007, Favier Dubois et al. 2009). Today, this area has a great biodiversity, such as a reproductive colony of sea lions ( Otaria flavescens ) which has recently formed (Svendsen et al. 2009: 8) as well as a variety of seabirds. Artifact sampling was focused on the area of greatest density of lithic artifacts, currently close to the center of the islet (Figure 1). The context of recovery of these materials can be divided into three categories: A) common transit areas of penguins that give shape to paths free of vegetation; B) burrow entrances C) marginal spaces that correspond to sectors of debris accumulation (twigs and dry grass, feathers, Penguin carcasses) on the margins of the transit area (Figure 2). During sampling, the original position of the artifacts, or face of recovery, and context of discovery were recorded. At the lab, general typological (tool, core, or debitage), raw materials, metrics (volume in mm3), and taphonomic variables were registered. The latter in particular were used to characterize and compare both assemblages. The recording and analysis of artifact modification due to taphonomic processes is a line of research to approach the intensity of the physical transformations in the archaeological context, and to indicate their degree of integrity (Schiffer 1983; Burroni et al. 2002). The variables recorded were as follows, the level of weathering in each tool face (W: W0, W1, W2, W3); the presence of carbonate concretion; and the integrity of the piece (whole or broken). The results show that intensive penguin traffic and burrow activity exposed buried materials in certain sectors (Figure 5.1), which are pushed through paths with no vegetation (Figure 5.2) and redeposited in “fall off” areas with little or no circulation (Figure 5.3). These are mostly small patches of vegetation and organic waste, which have high relative stability. For this reason we believe that in these patches, materials are more likely to accumulate and perhaps re-enter into the substrate. Preliminary evidence obtained for this study area suggests that the lithic record is in continuous formation, in this case because of the action of penguins. Since the establishment of this colony is recent, its impact on the archaeological record is significant.

Study of the energy investment applied in the manufacture of stone tools from San Matias Gulf coast (Rio Negro, Argentina) during the Middle and Late Holocene Lithic technology is one of the many strategies that past human groups primarily utilised to extract and process resources for consumption. Different artefacts can be manufactured by investing different amounts of energy (while some of them require a great effort to be produced, others can be produced with very little investment of energy), depending on factors such as raw materials availability, the purpose for which the instruments are made, the temporal constraints, among others. This energy investment can be measured by different indicators. It is expected that in an environment where the spatial and temporal variability results in a heterogeneous distribution of resources, the sets of artefacts will show greater energy investment in order to be more efficient to exploit and process the necessary resources. The opposite would occur if energy is randomly distributed in the environment (Torrence 1983; Jeske 1992; Bousman 1993). The area of this study is the San Matias Gulf coast (Rio Negro province, Argentina). Because of its geomorphological and structural differences, this coast has been divided into two distinct areas: the northern sector (between San Antonio Oeste city and El Condor), where there is a combination of accessibility to marine resources, of fresh water and an abundant availability of lithic raw materials and topographic shelters (Borella et al . 2007; Cardillo & Favier Dubois 2010); and the western portion (between Las Grutas city and the border with Chubut province), which is environmentally more homogeneous and with a lower variety of marine resources (Orensanz et al . 1973), and would have been used less intensively than the other portion of the gulf (Borella et al . 2007; Favier Dubois & Borella 2011). The dates of the northern sector go from ca. 6000 to 450 14C years BP (Favier Dubois et al . 2009a), while the dates of the western sector go from ca. 3000 to 900 14C years BP (Borella et al . 2015). In order to distinguish differential efforts put into the manufacture of lithic artefacts, this paper presents the results of the application of the concepts of "technical class" (Aschero & Hocsman 2004) and "utilitarian design" to the lithic assemblages recovered in the study area. The first concept considers overlapping flake scars that may fully or partially cover the surface of one or both sides of the instrument, intersecting or not at the tool’s middle axis (Aschero & Hocsman 2004). Categories within the technical class are not separated compartments but, according to Hocsman & Escola (2007: 76), there is a continuum in the morphology of artefacts ranging from those that can be produced with little effort, to those for which manufacture involves a greater effort. This approach is complemented by the study of utilitarian designs of instruments. This methodology was used in order to distinguish differential efforts in the manufacture of various artefact types found in the archaeological assemblages analysed, and to discern trends in the use of the different rock types found in the archaeological record. All of the analyses were performed according to the criteria established in Aschero (1975; 1983), whereas the identification of raw materials was made according to Alberti & Fernandez (2015). Finally Chi 2 test were run in order to determine whether the detected intra- and inter-coastal differences are statistically significant or not. For the northern coast of the gulf, the results indicate a general low energy investment, which goes along with the exploitation of marine resources during the earliest occupation periods. This is supported by the high percentages of blanks obtained using indirect percussion, by the absence of requirements of blank manufacture and by the absence of an imposition of requirements of form. Towards the later periods of occupation, the results indicate an increase in energy investment as part of an increased risk and diet diversification, since there is a rise in the manufacture of instruments by bifacial thinning. This could possibly be related to the emergence of new technologies such as projectile points needed to capture terrestrial resources. On the west coast of the gulf, however, the energy invested in the manufacture of artefacts would have remained constant over time, with the predomination of low energy investment throughout the occupation. Through the study of energy investment indicators, it could be established that a change in the energy investment put into the manufacture of instruments would only have taken place in the northern coast of the San Matias Gulf. This is related to a diet diversification that has been proposed for the area (Favier Dubois et al . 2009a). However, within this overall low energy investment for early periods of the occupation, there would have been a slightly higher investment on the west coast. A plausible explanation for this is the form in which raw materials appear in the environment and their quality for flaking activities. On the northern coast these sources are abundant and ubiquitous and of regular to good quality, while those on the western coast are located in specific places and their quality is better (Alberti 2015: 239-247). So, it is thought that due to higher efforts of rock provisioning on the west coast, technology would have tended to be conservative ( sensu Nelson 1991), with more energy invested in the manufacture of instruments in order to extend their use-life. On the northern coast, however, the greater availability of rocks would have led to a rapid disposal of the artefacts, which would have been manufactured with low energy investment. For later periods of the gulf’s occupation, an increase in energy investment was registered only for the northern coast. Therefore, the incorporation of land resources to the diet involved changes only in this region. It is possible that on the west coast the energy invested in artefact manufacture since the earliest times in relation to the availability of raw materials in the environment would have been enough for the extraction, processing and consumption of the new resources added to the diet in later times. This study establishes yet another indicator that reinforces the idea of a more dynamic and changing occupation of the northern coast of the San Matias Gulf, according to a heterogeneous distribution of food resources, and a more homogeneous use of space on the western coast, concordant with a reduced variety of resources in the environment.