The Petrographic Analysis of Sherds from the Musgano Site (41RK19), Rusk County, Texas

Repository Citation Tomka, Steve A.; Love, Lori B.; and Perttula, Timothy K. (2014) "The Petrographic Analysis of Sherds from the Musgano Site (41RK19), Rusk County, Texas," Index of Texas Archaeology: Open Access Gray Literature from the Lone Star State: Vol. 2014 , Article 23. https://doi.org/10.21112/.ita.2014.1.23 ISSN: 2475-9333 Available at: https://scholarworks.sfasu.edu/ita/vol2014/iss1/23


INTRODUCTION
Characterizing the mineralogical composition of ceramic vessels and sherds from Caddo sites in East Texas by means of petrographic analysis provides a unique opportunity to gather and investigate empirical evidence from ceramic vessels on : (1) technological and manufacturing practices, and (2) their trade and exchange at varying scales conducted by ancestral Caddo people with their neighbors, both near and far (i.e., other ancestral Caddo groups as well as non-Caddo communities). This evidence in turn can be used to explore changes in the nature of social and economic relationships between particular Caddo groups and - 2013) can also be employed to explore functional and technological differences in vessel function and form.
It is important to build on existing petrographic studies of Caddo vessels and vessel sherds (see Perttula and Selden 2013) by examining unstudied assemblages to (1) better clarify the compositional nature of these ceramic wares across the Caddo temporal and geographic landscape; (2) to help pinpoint other ceramic manufacturing locales and mineralogical compositional groups, but also to assess their apparent technological complexity; and (3) lead to better evaluations of the regional character of prehistoric and were changes through time in the direction and intensity of local and long distance trade and interaction. The disparate pieces of information contained within the sherds and vessel fragments of Caddo ceramics found on many prehistoric and early historic sites throughout the region have the potential to address these questions and research issues, and can contribute unique information concerning those relationships that existed in the distant (and not-so-distant) past between Caddo farmers. Twenty decorated sherds from the Musgano ceramic assemblage curated at the Texas Archeological Research Laboratory at The University of Texas at Austin (TARL) were selected for petrographic analysis. The sherds were split and one of the remaining fragments of each pair was used for the production of thin sections. Originally, the other half of each sherd was to be submitted for instrumental neutron activation analysis, but such analyses were not done; the remaining sherd fragment was returned for continued curation at TARL. Upon the receipt of the thin sections, they underwent petrographic analysis as reported on herein.
incised, incised-punctated (from Maydelle Incised, Weches Fingernail Impressed, and Washington Square Paneled vessels), and punctated decorative elements. Ten percent of the sherds are from bone-tempered vessels, based on macroscopic examination, while the others are from grog-tempered vessels.

PETROGRAPHIC ANALYSIS METHODS
The thin sections were examined with a Leica DM750P Petrographic microscope with an attached metheir general characteristics and taking photomicrographs of representative portions of each thin section.  Incised; grog-tempered RK19-13/65 UT00877 body, CB rectilinear and curvilinear engraved elements; grog-tempered; Perttula 2015: Figure 14f with tool punctates; Maydelle Incised; grog-tempered;   The general characteristics recorded were paste matrix descriptions, paste color, b-fabric (Stoops 2003:95), and description of edges. Two photomicrographs, one in plane light and another in cross-polar light, were Camera attached to a Dell computer.
The second step involved point counting using the Glagolev-Chayes method. The Glagolev-Chayes method involves using the mechanical stage, which allows one to move the thin section at a given interval beneath the crosshairs in the ocular, and identifying and recording each point encountered in the crosshairs the stage was set so that the vertical and horizontal increments were both 0.4 mm. Each point encountered by tally; however, for all voids and non-plastic inclusions, estimated size and shape were recorded. Nonplastic inclusions and voids were only counted once even if the same void or inclusion was encountered more than once in the crosshairs. Once the point counting was completed, non-plastic inclusions that were noted during the scanning of the slide but not included in the point counting were recorded using a general estimate of their frequency.
The thin sections were point counted until 200 paste points were reached. Stoltman (1989:151-152, 2012:H-1) suggests that a minimum of 100 points (exclusive of voids) are needed to ensure reliable results and that point counting in excess of 200 points yields redundancy. To reach the minimum of 200 paste points counted for each slide, the minimum number of points recorded was 231, and the maximum number of points recorded was 315 (see below). The counts, measurements, and paste, voids, and non-plastic inclusion type recorded during point counting for each thin section were input into a JMP Pro 10 data table.
The maximum diameter of the inclusion/void was measured with the ocular scale to the nearest whole count was recorded for each inclusion, input into JMP and converted to an actual size. Within each temper category, the distribution of sand was noted by size category based on the Wentworth Grain Size scale (Table 2).

Sherd ID
The ID number etched on the thin sections.
This lists the percentage of each category found during point counting. Note that the "other" inclusion category was omitted from this table.

Median Sand Size
This represents the median size for the sand inclusions in the thin section.
The median inclusion size represents the median size for all inclusions excluding sand and voids.

Journal of Northeast Texas Archaeology 49 (2014) 47
This lists whether or not these inclusions were rare (R), uncommon (U), common (C), and abundant (A).

The temper
As indicated earlier, there was a broad range in the point counts of the 20 thin sections from the Musgano site. Table 3 presents the number of aplastic inclusions and voids per thin section. The lower the total number of points counted (i.e., 200 paste plus voids and aplastic inclusions), the less frequent the number of aplastic inclusions, while the higher the number of points counted, the more frequent the number of aplastic inclusions in the ceramic fabric.

Aplastic Point Count Group
Sample number/ Thin section sherd ID Table 3 indicates a peak in point counts at 41-50 inclusions and voids (35 percent of the slides). The the bulk of the inclusions are quartz, and other sand constituents that are part of the parent clay. - The "other" category was not used in temper assignments given that this category made up a small fraction of the most common category represented, followed by thin sections tempered with bone. All of the ceramic vessels were made of sandy paste clays. These nine thin sections represent clay fabrics tempered with grog. The grog temper seen in these thin sections is itself tempered with bone. Therefore, the bone occurs only occasionally in the clay fabric of the thin sections, but it is consistently noted in the pieces of grog that are used as the aplastic additive to the clay.
1, consisting of seven sherd specimens (4, 5, 8, 12, 15, 18, and 20), bone aplastic additives never register in the point counting at a rate higher than 1 percent of the counted aplastic inclusions. As a matter of fact, during the initial scanning of the slides but never occurred in large enough numbers to actually be found in the counting cross-hairs. In sub-group 2, consisting of two thin sections (7 and 10), bone tempering makes up 7 percent and 3 percent, respectively, of the point-counted inclusions.
Grog makes up between 1-6 percent (mean of 3.3 percent) of the aplastic inclusions noted in the nine The major difference between the sub-groups is in terms of the percentage of bone tempering in the thin sections. It is possible that in the case of the seven specimens with low bone percentages, the only bone derives from the processing of the bone-tempered grog added to the clay fabric. On the other hand, the higher percentages of bone tempering in the sub-group 2 specimens may be due to bone deriving not only from the bone-tempered grog but also as an additional additive to the clay fabric.
Given that the majority (68 percent) of the sand in each of the thin sections is silt-sized (Table 5), it is likely that the sand was a natural constituent element in the clay for all the samples in this category. Both the percentage of sand in the paste, as well as the size of the sand grains, suggests that the sand is a natural constituent of the clay fabric. As such, the group of vessels represented by these thin sections appear to be made of the same clay. In addition, the percentage of grog present in the fabric of these specimens is very similar. Taken on the whole, the two temper sub-groups appear to be made by the same craftswomen or using the same technological steps and procedures, with the exception of the grog employed as the aplastic additive. The absence of bone in Temper Group II and its presence in the grog temper of Temper technological approach employed by the same Caddo potters to make clay vessels. Also present: mica (common; tiny rods); alkaline feldspar (uncommon), hematite (uncommon). Also present: mica (common, various forms); bone (common); rock conglomerate (uncommon); polycrystalline quartz (uncommon); plagioclase (rare). Also present: chert (uncommon); bone (rare); hornblende (uncommon). Common temper found in grog: small bone.

Inclusion Size (mm):
Ra ng e M e a n M e di a n   Also present: bone (rare); plagioclase (uncommon); rock conglomerate (rare); chalcedony (rare). As indicated earlier, these two slides are considered to be from a sub-group of Temper Group I due to the higher percentages of bone temper noted in them during the petrographic analysis. It is likely that the two vessels represented by these sherds may actually contain bone temper not only derived from the bonetempered grog present in the fabric but also as an additional additive to the clay fabric.  Also present: mica (common, various forms); polycrystalline quartz (uncommon); plagioclase (uncommon); hematite (abundant).  : 1, 2, 6, 9, 14, 16, 17) Each of the seven thin sections in this group contain both grog and sand constituents in the paste. The the point counting.
The size analysis of the grog and quartz particles also is informative about whether the sand present in the paste is a purposefully added aplastic inclusion or simply a natural constituent of the parent clays employed in the manufacture of the pottery. Table 6 lists the breakdown of grog and quartz within the seven thin sections placed in this temper group. The large majority of the grog particles fall in the coarse and very coarse sand size categories (i.e., 0.5-1.0 mm and 1.01-2.0 mm size groups). This is not surprising given that the reduction of pieces of pottery to sand size classes (0.02-0.06 and 0.07-0.12 mm). Only a small fraction of the quartz falls in the medium sand size group, suggesting that the quartz is a natural constituent of the clays rather than an aplastic additive. Regardless, however, the presence of sand does perform the same function in the clay fabric, namely increasing thermal shock resistance.  Also present: mica (common, various forms); plagioclase (common); hematite (uncommon); chert (common). Also present: mica (uncommon; tiny rods); hematite (common); plagioclase (rare). Also present: crystalline quartz (rare); hematite (uncommon). Two thin sections are included in Temper Group (TG) III. Both were from vessels made using the same sandy clays employed in the making of the vessels grouped into TG I and TG II. The percentage of sand in mean of sand in the clay fabric of either TG I or TG II. As such, it may be indicative of the use of a distinct clay source compared to the one used in the making of the TG I and II vessel thin sections.  sandy paste clay seen in the previous groups of thin sections. Sandy inclusions constitute 20 percent and 16 percent of the point counted aplastic inclusions, respectively. In addition, neither has grog tempering in the clay fabric. However, the two thin sections differ in terms of the quantity of bone temper noted in the paste. One specimen has a few large pieces of burnt and ground bone but the numbers were so small that they were never counted during the systematic point counting. The other specimen has a large (14 percent) percentage of bone.

SUMMARY AND CONCLUSIONS
recovered from the Musgano site (41RK19) revealed that all of the sherds appear to have been made of the same sandy paste parent clay fabric and are thus of local manufacture. In addition, four temper groups were resented by Temper Group I, subgroup 2 (100 percent), while between 42.9-50.0 percent of the sherds in the other temper groups are utility wares. The same range of decorative elements from similar types (primarily Maydelle Incised) are present in the utility wares in Temper Groups I-II, and IV, including incised, incised-punctated, and tool punctated decorations, while the one brushed-appliqued sherd thin section falls temper recipes (50.0-57.1 percent), while engraved wares are absent in Temper Group I, subgroup 2 thin sections, and uncommon (28.6 percent) in Temper Group I, subgroup 1 thin sections.
The most common temper in the fabric of the sherds from the Musgano site is grog. Two kinds of grog temper were used in the manufacture of the new vessels. One group of vessels (Temper Group I) is tempered with grog that itself was tempered with bone. Nine thin sections are included in this temper group. Bone appears in very small amounts in both the grog pieces as well as in the clay fabric of the newly-made vessels. It is likely that the bone in the clay fabric derives from the processed grog. Two sub-groups of thin sections can be differentiated in this temper group. Seven of the nine specimens contain only minimal amounts of bone, typically less than 1 percent of the point-counted aplastic inclusions. The remaining two specimens can be considered as members of a second sub-group because they contain bone temper ranging from 3-7 percent of the point counts, suggesting that perhaps additional bone was added to the clay fabric itself. The second group of vessels (Temper Group II) are tempered with grog that contains no bone. Seven specimens are included in this temper group. The sandy grog appears to be of the same clay fabric as the clay from which the vessels are actually made. The fact that two distinct grog types are employed in the making of sandy paste vessels may indicate that technologically there is no difference in the manufacture of vessels with bone-tempered grog versus un-tempered grog, which seems supported by the fact that both utility wares use of bone-tempered grog in the manufacture of otherwise sandy and non-bone temper-containing vessels may be an indication of social relationships and cultural transmission between Caddo potters of distinct but nearby traditions (i.e., a contemporaneous bone-tempered tradition exists in the Angelina River basin and four thin sections. Temper Group III consist of two specimens that are un-tempered with the exception of the sand constituent in the sandy paste clay fabric. The two specimens in Temper Group IV contain bone tempering in the typical sandy paste clay fabric seen in all of the thin sections from the Musgano site. There is no evidence of grog in these two thin sections, suggesting that the bone present in these two specimens may represent a distinct technological tradition of vessel manufacture from the grog-tempered specimens, and distinct technological and functional differences have been detected in the manufacture of Caddo utilindividual variability in technological approaches to ceramic vessel manufacture and use.