Ancient Firing Research Articles

The firing temperatures of burnt clay from the Chinese neolithic cultural relics and its paleoenvironmental imprints

The impact of human-induced fires on the surrounding environment has been particularly significant during the Anthropocene epoch. Neolithic burnt clay, which is widely distributed in the archaeological relics of ancient civilizations across the Eurasian continent, provides pivotal information about the ancient firing stories. However, understanding of the paleoenvironmental imprints of fire in burnt clay has been largely limited by the lack of sufficient analytical data on comprehensive knowledge of ancient firing conditions. In this study, a detailed magnetic analysis was conducted on burnt clay materials from a Neolithic site in Fujian, southeastern China, which presented a burnt clay-based record of the Neolithic firing temperature in relation to paleoenvironmental conditions. Based on magnetic analysis, the ancient firing temperature was determined to be approximately 620 °C, which is comparable with other records from Eurasian Neolithic sites. Frequency-dependent magnetic susceptibility provides alternative indicative information for ancient firing conditions in addition to conventional magnetic susceptibility. Furthermore, magnetic properties of burnt clay may decode the in-situ source characteristics with respect to geological background. In addition, a potential link between temporal variations in ancient firing temperatures in burnt clay and surrounding paleoenvironmental changes is tentatively interpreted by local environmental feedback of temperature-moisture conditions and anthropogenic activity. This study further confirms the archaeological potential of thermomagnetic properties as useful indicators in paleoenvironmental studies. More work combining paleoenvironmental and archaeological archives is critically essential to understand ancient firing history in the context of environmental conditions.

Geomagnetic field variations and low success rate of archaeointensity determination experiments for Iron Age sites in Bulgaria

The geomagnetic field variations during the Iron Age (last 1200 years BC) are poorly constrained for Bulgarian territory due to the scarcity of archaeological sites with a well-established chronology. Additionally, the collected Iron Age materials frequently fail to provide reliable archaeointensity data. In an effort to expand the Bulgarian archaeomagnetic database for the last millennia BC and to find an explanation for the low success rate of Thellier experiment, 28 baked clay structures from 10 archaeological sites were archaeomagnetically studied. Magnetically soft minerals dominate in all collections despite the variety of the sampled structures (hearths, domestic ovens, ovens, pottery kilns, burnt dwelling remains, mud-bricks), which suggests differences in the ancient firing conditions. The main carriers are magnetite/titanomagnetite and/or maghemite/titanomaghemite. Verwey transition is well expressed in most samples. Usually more than one magnetic phase exists and noticeable mineralogical transformations occur during laboratory heating. Regardless of all the pre-selection criteria applied, the total success rate of intensity determination is quite low (21%), which seems to be typical for Bulgarian Iron Age materials. At this epoch that starts with a significant decline in the quality of material culture, combustion structures are usually poorly preserved, short-term used (frequently only once) and heated to temperatures around and below 600 °C. A clear relationship is observed between median destructive temperature and success of intensity determination, which suggests that this parameter have a potential as a pre-selection criterion.The new data double the Bulgarian archaeomagnetic dataset for the period in concern with 18 directional and 7 intensity results (6 full vectors). An inclination and intensity decrease is outlined at around 400 BC with assumed variation rates 0.10°/year and 0.32 μT/year, respectively. Considering the whole database, three intensity peaks are detected at circa 1050 BC (Fa ~ 78 μT), 550–500 BC (Fa ~ 96 μT) and 300 BC (Fa ~ 80 μT). The second peak is the highest over the entire eight-millennium long Bulgarian archaeomagnetic record. The first half of the Iron Age (1200–600 BC) is characterized with easterly declinations reaching ~18°E around 1150 BC, while in the last half it turns westerly with westernmost values around 400 BC. The current state of Bulgarian archaeomagnetic reference curves for the Early Iron Age is not sufficient for precise archaeomagnetic dating. Although the resulting dating interval for Ryahovets oven (the only structure with uncertain archaeological dating) coincides with the archaeological evidence, it spans more than 200 years. In such a case, correlation with other archaeomagnetically studied sites from the corresponding period can be especially helpful.

Archaeomagnetic knowledge of the Neolithic in Bulgaria with emphasis on intensity changes

Abstract Several archaeological baked clay structures from Bulgarian Neolithic sites were archaeomagnetically studied. According to the ancient firing conditions, the collected materials are dwelling remains and ovens with different heating histories. The variability of magnetic properties is greater in the burnt dwelling remains compared to the ovens. The prevailing magnetic minerals are magnetite/titanomagnetite and epsilon iron oxide. Less often, the presence of hematite is suggested. For one of the ovens, a well-pronounced evolution in magnetic properties was observed between its successive levels. The collected materials possess stable magnetic mineralogy and the success rate of archaeointensity determination experiment is 84%. The experiment completely failed only for the structure where epsilon iron oxide is not identified and where the lowest median destructive fields are determined. The obtained archaeomagnetic results are summarized as 10 new reference points. The structures subjected to the same firing event are combined as one feature. Their dating is based on well-established relative Neolithic chronology and stratigraphic constraints. The new data coincide fairly well with the Bulgarian dataset and with the data available for the neighbouring countries, confirming an intensity maximum around 5550 BC and a minimum around 5400 BC. No indications of geomagnetic ‘spikes’ or ‘jerks’ are detected.

Rock-magnetic and color characteristics of archaeological samples from burnt clay from destructions and ceramics in relation to their firing temperature

Determination of ancient firing temperatures of archaeological pottery is a widely discussed topic in archaeometry. Here, a set of magnetic characteristics (magnetic susceptibility, isothermal and anhysteretic remanences, hysteresis parameters) and color parameters were studied for a collection of pottery fragments and burnt clay from house destructions. The results show that magnetite and hematite of superparamagnetic to single domain grain size are the main iron oxides produced during heating. Hematite fraction is more important and frequently detected in pottery sherds than in burnt clay from destructions. An inverse linear regression was obtained between the estimated firing temperature and the ratio value/chroma, which is shown to be site specific for pottery samples. For burnt house destructions, the regression is less well constrained and most probably reflects differences in the raw material. Consideration of rock-magnetic parameters against firing temperature estimates reveals a direct link between saturation magnetization and ancient firing temperature for burnt clay from house destructions. In contrast, this link is inverse and worse defined for pottery materials. This different behavior is attributed to different prevailing processes of iron oxide transformations in burnt clay and pottery, related to the specific firing conditions.

Magnetic measurements as indicator of the equivalent firing temperature of ancient baked clays: New results, limits and cautions

Abstract We present new experimental results on the variation of the magnetic properties of baked clays as a function of the temperature reached during laboratory treatments. Such experiments, including continuous monitoring of the magnetic susceptibility and magnetic moment versus temperature, were applied to a set of natural clays experimentally heated in the laboratory at 200 °C, 400 °C and 600 °C as well as to archaeological baked clays collected from two archaeological sites in Northern Italy (Santhia and Carbonara Scrivia). The aim of this study is to investigate the reliability of the magnetic properties to identify the equivalent firing temperatures of ancient baked clay artefacts based on the reversible behavior of thermomagnetic diagrams. The results obtained indicate that the magnetic properties do not always succeed in estimating the firing temperature of the baked clays, mainly when clays have been heated only once and at relatively low temperatures, e.g. less than 300–400 °C. On the contrary, magnetic properties of ancient clays that have been repeatedly heated at the past at temperatures higher than 400 °C appear to be more stable and representative of the equivalent firing temperature. This study confirms that the reversibility of thermomagnetic curves can be a useful indicator of ancient firing temperatures in the case of baked clays that have experienced multiple heatings at the past while caution should be paid on its general use as archaeo-temperature marker.

Thermoanalytical investigations of ancient ceramics

The review consists of four parts. Part I is about the thermal transformation in clay minerals under firing and about the properties of fired clay. The transformations in the clay are expressed quantitatively with the extent of conversion, α, which is the function of two parameters of firing process, time t and temperature T: α = f(t, T). Part II is about the estimation of firing temperature after the analysis of the products of firing clays. All the estimations are speculative, without mathematical equations. It is impossible to derive the value of only one variable T from α = f(t,T), the function of two variables. Part III is about the long-term inverse transformation in fired ceramic paste under ambient conditions. The mass gain as a function of time is used for the evaluation of the time elapsed from the ancient firing, t. Part IV is about the visualization of the extent of conversion of the clay in the paste after all direct and reverse reactions, i.e., α.

A Mineral Magnetic Approach to Determine Paleo‐Firing Temperatures in the Neolithic Settlement Site of Mursalevo‐Deveboaz (SW Bulgaria)

AbstractArcheological remains from the Neolithic period in SE Europe are characterized by the presence of massive burnt daub relics sintered at high temperatures. These findings raised the hypothesis of deliberate house burning as a strategy for ensuring the survival of place and the development of social memory in Neolithic society. Although highly discussed in the archeological community, analytical data on the ancient firing temperatures achieved during burning Neolithic houses are missing except an empirical study determining firing temperatures according to the color of burned clay. The Neolithic site Mursalevo‐Deveboaz (Bulgaria) is one of the largest known settlements consisting of more than 70 houses. Rock‐magnetic analyses are applied for characterization of iron oxides produced during firing, and the firing temperatures were estimated using the magnetic susceptibility method. Results on a collection of 445 samples show the presence of very fine grained magnetite/maghemite and hematite. Magnetic data are supported by elemental analysis, reflectance spectroscopy, and scanning electron microscopy. The data suggest an increase in the magnetic grain size from superparamagnetic toward single domain with increasing firing temperature. Firing temperature estimates for 148 samples of different color vary between 680 and 1,140°C. Comparing the magnetic properties of iron oxides identified and literature data on solution‐combustion synthesis of iron oxides allowed a mechanism behind the extreme firing of Neolithic houses to be suggested. Our study proposes for the first time that combustion synthesis of iron oxides could explain the extreme house burning in many Neolithic settlements achieved through intentional addition of wood, dung and urine.

Firing temperatures of ceramics from Bulgaria determined by rock-magnetic studies

Maximum firing temperatures were determined for a large (198 samples) and variable collection of ceramic sherds from Bulgaria using magnetic susceptibility measurements. The data obtained were combined with the existing archaeological evidences as a first attempt to elucidate the technological development of pottery production in four important Bulgarian archaeological sites – Plovdiv, Pliska, Veliki Preslav and Dragovishtitsa. The results obtained confirm that magnetic susceptibility method is a very effective and precise tool for the determination of ancient firing temperatures, which overall vary from 550°C to 1010°C. Regardless of the great variability of the samples studied (according to their archaeological context, technological characteristics and purpose of usage); the results point out that maximum firing temperatures increase with time. Furthermore, in the earlier periods, firing temperatures of cooking and serving wares are distributed in similar ranges. Thus, the purpose of usage of the vessels has not been decisive about their manufacturing. The technological development in later periods obviously leads to the improvement of the quality of the serving vessels first and of the cooking pots after, but the highest firing temperatures are principally related to serving potteries and especially to the glazed ones. The results obtained for Pliska and Veliki Preslav, located relatively close to each other, indicate that during 10–11 c. CE serving vessels have been produced at higher temperatures in Veliki Preslav in comparison to Pliska but there is no such a difference for the cooking pots. This agrees well with the different status of both settlements at that time. Further expansion of the study by analyzing greater number of well-stratified samples of different types and quality, grouped in type-technology sets could allow finding more precise and common characteristics and trends, which could be compared in synchronous archaeological sites.

Optically stimulated luminescence dating of hearths from the Fazzan Basin, Libya: A tool for determining the timing and pattern of Holocene occupation of the Sahara

Circular concentrations of burned stone fragments are widespread in the Sahara, and are generally interpreted as ancient hearths. These hearths provide a rich resource for reconstructing the pattern and timing of Holocene human occupation of North African drylands. However, this resource has not been fully exploited since only 5% of hearths contain dateable carbon, and collection of this carbon frequently results in the destruction of the hearth. Previous research indicates that anthropogenic firing empties the optically stimulated luminescence (OSL) source traps of quartz grains within hearth rocks. Consequently, the quartz OSL signal should provide a means for determining the time elapsed since last firing of Saharan hearths. To test the applicability of this approach to Saharan hearths, samples were collected from a site in the Fazzan Basin, and analysed using single-grain OSL. Equivalent dose–depth profiles through hearth rocks demonstrate that they are sufficiently opaque to preserve a record of ancient firing. Comparison with unfired parent material indicates that anthropogenic firing of hearth rocks was sufficient to empty the OSL source traps. The OSL ages for hearth rocks are internally consistent and suggest use around 8 ka. Our study demonstrates that OSL dating is a viable tool for determining the timing and pattern of Holocene occupation of the Sahara.

Thermal characterization of ancient hearths from the cave of Les Fraux (Dordogne, France) by thermoluminescence and magnetic susceptibility measurements

Numerous sorts of evidence of fires were observed in the cave of Les Fraux (Dordogne, France) and in particular the effects of fire on sediment were studied for a better understanding of their use centuries ago. Our present objective is the evaluation of the firing intensity by determining the past temperature (paleotemperature) attained by the topmost sediment of the archaeological fires. The principle of paleotemperature determination is based on the thermoluminescence (TL) properties of quartz and the magnetic susceptibility of the sediment. By comparing the TL signal of anciently heated quartz to the TL signal of thermal references made in the laboratory, we were able to obtain a maximal equivalent temperature attained for each sample extracted from ancient fires. The magnetic susceptibility (previously measured on the hearth surface) could thus be estimated as a function of temperature. The main result of this study is the temperature mapping of the hearth which can be used as meaningful information about the ancient firing intensity.

Estimation of ancient firing technique by the characterization of semi-fused Hellenistic potsherds from Harabebezikan/Turkey

This study discusses the availability of different ancient firing techniques for some semi-fused potsherds which were recovered from an archeological excavation carried out for a Hellenistic workshop at Harabebezikan (Turkey). There are different ancient firing techniques such as open or surface firing (bonfire), pit firing and kiln firing. Each firing technique may create different effects on pottery. It sometimes may be possible to distinguish the firing technique used for a pottery if some evidential characteristics of firing could be defined. The potsherds were characterized with different analytical techniques in order to enlighten firing technique used for the production. Wavelength dispersive X-ray fluorescence (WDXRF) and X-ray diffraction (XRD) analysis were performed for chemical and mineralogical/phase contents, respectively. Scanning electron microscopy (SEM) in combination with energy dispersive X-ray spectrometry (EDX) was further performed for microstructural and microchemical characterization. Quartz (SiO2), calcite (CaCO3), plagioclase [(Na,Ca)AlSi3O8], hematite (α-Fe2O3), pyroxenes [Ca(Mg,Al)(Si,Al)2O6]/[Ca(Mg,Fe)Si2O6], akermanite (Ca2MgSi2O7) and leucite (KAlSi2O6) were identified in the samples. Abundance of new mineral formations in the samples, related firing temperatures, microstructural and microchemical investigations suggested that kiln firing was the most probable technique for the production of the investigated potsherds.

Influence of firing conditions on ceramic products: Experimental study on clay rich in organic matter

The effect on ceramic products of firing conditions in the presence of abundant organic matter is assessed here experimentally by reproducing two ancient firing techniques: pit firing, characterised by a high heating rate and short residence time in a reducing atmosphere; kiln firing, with a low heating rate and long residence time in an oxidising atmosphere. As expected, pit firing conditions produced uniformly reduced ceramics, and gehlenite, diopside and spinel occurred at suitable temperatures (above 900 °C). Interestingly, in kiln firing conditions, sandwich structures formed in the ceramics, in which mineral assemblages and Fe oxidation state turned out to be different in the black core with respect to the margin. Spinel, cordierite and metallic Fe formed in the core, whereas hematite and spinel, in addition to gehlenite and diopside, crystallised in the margin at suitable temperatures (above 800 °C). Therefore, despite the oxidising atmosphere of the firing, reducing conditions occurred in the core, suggesting sluggish oxygen diffusion within the pottery. In addition, decomposition of reactant mineral phases and crystallisation of new mineral products in pit firing conditions occurred at temperatures about 50 °C higher than in kiln firing conditions, indicating that residence time strongly controlled reaction kinetics, as higher temperatures (i.e., a higher degree of reaction overstepping) are required when residence time is lower. On the contrary, illite broke down at a lower temperature than expected in both sets of firing conditions. This is interpreted as the effect of reduced water fugacity caused by burning of the organic matter.

Effects of thermal treatment on TL and EPR of flints and their importance in TL-dating: application to French Mousterian sites of Les Forêts (Dordogne) and Jiboui (Drôme)

This study of trapped charge phenomena in flint highlights the influence of laboratory thermal annealing conditions on TL properties and age evaluation. The effectiveness of thermal zeroing of geological, or weakly heated flint, is investigated by EPR and TL; the 380 °C TL peak (correlated to the Al centre) is totally erased after heating at 300 °C for 20 min and the 470 °C TL component (OHC centre) after heating at 400 °C for 20 min. We attempt to determine laboratory conditions of annealing that lead to a state of trap distribution and charge filling that is closest to that the archaeological material had after its ancient firing. Under these conditions, the original mode of TL growth with dose is expected to be more appropriate; consequently, more reliable TL ages should be obtained using the standard TL protocol. The way to determine appropriate annealing conditions is the result of a coupled TL–EPR study: EPR characterisation of organic radicals and evolution of the E ′ centre according to Toyoda et al.'s protocol (1993) together with the evolution of regenerated glow curve shapes and TL sensitivity with the thermal treatment. As an illustration, the following TL ages have been obtained with the assistance of EPR, on Mousterian flints from two French open air sites. The age of the Mousterian occupation at Les Forêts (Dordogne) 92.7 ± 4.5 ka , which fits into the palaeoenvironmental chronological frame, provides accurate information for archaeologists. The site of Les Forêts was the first open air Mousterian site found in south-west of France thanks to rescue excavations, in a region where cave and rock shelter sites essentially are known. The age of the Mousterian occupation at Jiboui Path (in the Alps, Drôme), 52.0 ± 2.6 ka , is consistent with possible seasonal occupation of altitude sites during warmer phases of the last Glacial period. As data for alpine area are rare, dating this type of site was of fundamental interest for the study of the (pre)history of populations.

03/01933 Influence of mineral precipitation and dissolution on hydrologic properties of porous media in static and dynamic systems: Freedman, V. L. et al. Applied Geochemistry, 2003, 18, (4), 589–606

The effect on ceramic products of firing conditions in the presence of abundant organic matter is assessed here experimentally by reproducing two ancient firing techniques: pit firing, characterised by a high heating rate and short residence time in a reducing atmosphere; kiln firing, with a low heating rate and long residence time in an oxidising atmosphere. As expected, pit firing conditions produced uniformly reduced ceramics, and gehlenite, diopside and spinel occurred at suitable temperatures (above 900 °C). Interestingly, in kiln firing conditions, sandwich structures formed in the ceramics, in which mineral assemblages and Fe oxidation state turned out to be different in the black core with respect to the margin. Spinel, cordierite and metallic Fe formed in the core, whereas hematite and spinel, in addition to gehlenite and diopside, crystallised in the margin at suitable temperatures (above 800 °C). Therefore, despite the oxidising atmosphere of the firing, reducing conditions occurred in the core, suggesting sluggish oxygen diffusion within the pottery. In addition, decomposition of reactant mineral phases and crystallisation of new mineral products in pit firing conditions occurred at temperatures about 50 °C higher than in kiln firing conditions, indicating that residence time strongly controlled reaction kinetics, as higher temperatures (i.e., a higher degree of reaction overstepping) are required when residence time is lower. On the contrary, illite broke down at a lower temperature than expected in both sets of firing conditions. This is interpreted as the effect of reduced water fugacity caused by burning of the organic matter.

Early Pottery Making in Northern Coastal Peru. Part II: Field Firing Experiments

We present data from three seasons of experimental field work designed to recreate ancient Andean coastal ceramic firing techniques. Based on the recent discovery of two different archaeological ceramic production sites in the La Leche river valley of northern coastal Peru, the opportunity arose to apply Mossbauer spectroscopy and other analytical methods to reconstruct ancient firing procedures. Two sets of firings took place in 1993 and 1997 in Batan Grande using a partially restored Formative kiln from about 800 BC, local hardwood and cow dung as fuel. A third experiment followed in 2000 after the discovery of a Middle Sican ceramics workshop in use between ca. AD 950 and 1050 at Huaca Sialupe, where an exact replica of an ancient kiln was built from local clay, and fired with local wood and cow dung. Additionally, inverted urns found at Huaca Sialupe were tested for their potential use as furnaces for metal working. Mossbauer spectroscopy was used to compare the physical and chemical state of specimens produced in the field experiments with ancient ceramics and with specimens produced in controlled laboratory experiments.

Early Pottery Making in Northern Coastal Peru. Part IV: Mössbauer Study of Ceramics from Huaca Sialupe

We report on an interdisciplinary study of ceramic material excavated in 1999 and 2001 at a 1000-year old ceramic and metal production site, located at Huaca Sialupe in the La Leche valley on the north coast of Peru and dating to the Middle Sican period (AD 900–1100). Sherds of Sican red- and blackware, numerous moulds, several kilns and other evidence of pottery making were found. The pottery, in particular, is famous for its fine texture and perfect black surface finish. In addition, some clay lumps and sherds of unfired Sican pottery were excavated. Within the same workshop several large inverted ceramic urns used as furnaces were found together with Middle Sican metal working tools and debris. Various physical methods were applied to investigate this material. The ancient firing procedures could be elucidated by comparing the spectra observed for the ancient sherds with model spectra of laboratory and field fired clay samples. This shows that the fine ware made at Huaca Sialupe was intentionally fired under strongly reducing conditions at temperatures up to 900°C. Reoxidation at the end of the reducing firing took place only occasionally. Less care was taken in firing moulds used for pottery making.

Ceramics Technology at Late Classic K’axob, Belize

Excavation of a Late Classic Maya platform at K’axob, Belize, has revealed a suite of pit features and associated artifacts that are strongly suggestive of pottery production. Interpretation of the features as remnants of pit kilns used to fire pottery is bolstered by comparanda from the Andean region. Archaeometric and experimental replication studies also support the interpretation of this locale as one of pottery fabrication. Findings discussed include features identified as kilns, raw material suitable for temper, lumps of fired clay, ground stone, and expedient clay-working tools made of recycled pottery sherds. This research contributes to knowledge of the organization of Maya pottery production by providing the most comprehensive information presented to date on the technology of ancient Maya pottery fabrication and firing.

Firing techniques of the impasti from the protohistoric site of Concordia Sagittaria (Venice)

Relevant information on the technology employed in the production of concotto and coarse pottery was derived mainly by 57Fe Mössbauer spectroscopy. The concotto and the coarse pottery are two types of fired clay mixtures unearthed from the protohistoric settlement site of Concordia Sagittaria. The concotto pottery was produced by firing clay mixtures under oxidizing conditions at high temperatures in kilns, or at lower temperatures in open air. The firing of these clay mixtures, containing partially ground pieces of waste pottery, resulted in hard, impermeable and coloured construction materials, particularly suitable for humid environments. In turn, the coarse pottery was produced by firing clay mixtures less heterogeneous than those of the concotto. The firing was performed under reducing conditions at high temperature with a final exposition to air by opening the still hot kiln. This firing technique yielded light and agreeable coarse pottery with a red-coloured surface covering the grey–black core. Both the ancient firing techniques were substantially reconstructed by comparing the Mössbauer patterns of the artefacts with those of the replica samples produced from local clay fired in the laboratory.

Stable Isotopes of Carbon and Oxygen as a Possible New Tool for Estimating Firing Temperatures of Ancient Pottery

AbstractThe ratios of the stable isotopes of carbon (13C/12C) and oxygen (18O/16O) in calcite in clays that contain carbonate and that were fired at temperatures between 500 and 700 °C displayed a good correlation with the firing temperature for both isotopes. The isotopic composition indicated that the original carbonate was either completely decomposed or that it exchanged with environmental CO2 to obliterate the original isotopic signature. The isotopic effects seem to be kinetically controlled. The isotope thermometer is used to compare refiring temperatures of pottery which was fired under controlled conditions. The differences between calculated and actual temperatures did not exceed 132 °C and in most cases was about 50 °C or less. Isotopic analysis of pottery from Tel Miqne‐Ekron and Deir el Balah, dated to the 13th–12th centuries BC, gave an average ancient firing temperature of about 600 °C. If shown to be of general validity, then perhaps this technique can be used also for estimating preparation temperatures of ancient mortar, especially when preserved in dry climates where later changes would be minimized.

The Physical Nature of Nabataean Pottery

Previous articleNext article No AccessThe Physical Nature of Nabataean PotteryPhilip C. HammondPhilip C. Hammond Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by American Journal of Archaeology Volume 68, Number 3July 1964 The journal of the Archaeological Institute of America Article DOIhttps://doi.org/10.2307/502388 Copyright © 1964 by the Archaeological Institute of America. All rights reserved.PDF download Crossref reports no articles citing this article.