The Archaeology of Castle Rock Pueblo

Introduction

¹
This report synthesizes information on portable artifacts collected during excavations at Castle Rock Pueblo. Several analyses of Castle Rock artifacts and comparisons with other Pueblo III Mesa Verde–tradition sites in southwestern Colorado are presented. Artifacts from the test excavations conducted as part of the Sand Canyon Project Site Testing Program (Kleidon 1999*1; Pierce et al. 1999*1; Varien 1999*2) and from the intensive excavations of 1992–1994 are considered together.

²
Many of the tables and figures presented in this report were produced using the artifact databases as they existed in June 1998. Since that time a few minor provenience changes have been made, so there may be slight discrepancies between the data discussed here and those contained in the current database. It is unlikely that these changes affect any of the conclusions presented in this report on the basis of the June 1998 data.

Processing of Artifacts in the Laboratory

³
All objects collected during the excavations at Castle Rock Pueblo were processed according to Crow Canyon's standard laboratory procedures, which are described in the on-line laboratory manual.

Definitions of Analytic Categories

⁴
All objects were classified into various stone, bone, pottery, vegetal, and other categories, as defined in the on-line laboratory manual.

Disposition of Materials

Curation

⁵
All artifacts, ecofacts, and other samples collected from Castle Rock Pueblo, with the exception of wood samples submitted for tree-ring dating, are currently curated at the CANYONS OF THE ANCIENTS VISITOR CENTER & MUSEUM, 27501 Hwy. 184, Dolores, Colorado, USA. The collections are indexed to the artifact databases accessible through this report, and all curated objects are available for future study through the Heritage Center. Tree-ring samples that produced dates, along with samples that might potentially be datable in the future, are curated at the Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona, USA.

Repatriation

⁶
As of this writing, human remains and associated funerary objects collected during excavations at Castle Rock Pueblo are in the process of being repatriated according to the Native American Graves Protection and Repatriation Act (NAGPRA). The CANYONS OF THE ANCIENTS VISITOR CENTER & MUSEUM is curating these items during the repatriation process. Objects falling under the jurisdiction of NAGPRA are not currently available for study, and their future disposition has not yet been decided.

Destructive Analysis

⁷
A few artifacts have been subjected to destructive analysis, including small portions of certain white ware bowl rim sherds that were included in Glowacki's studies of pottery production and exchange using instrumental neutron activation analysis (Glowacki 1995*1; Glowacki et al. 1995*1, 1997*1, 1998*1). These sherds are identified in the "comments" field of the pottery data tables. Small portions of numerous sherds were also removed to facilitate temper identifications. Small portions of selected human remains from Castle Rock and other Sand Canyon locality sites were used for stable isotope analysis (Katzenberg 1999*1). Samples submitted for tree-ring dating that possessed little dating potential have been discarded by the Laboratory of Tree-Ring Research.

Additional Studies of Castle Rock Pueblo Artifacts

⁸
In addition to the analyses reported here, numerous other studies of artifacts from Castle Rock Pueblo have been conducted or are in progress. Pierce et al. (1999*1) reported on artifacts collected during the Site Testing Program portion of the excavations at Castle Rock Pueblo and at 12 other sites in the Sand Canyon locality (Varien 1999*2). Studies of white ware pottery designs that used sherds from Castle Rock include those by Hegmon (1991*1) and Ortman (1998*1, 2000*1). Variation in the manufacturing techniques used in the production of corrugated gray ware jars was examined by Dobshuetz (1999*1). Corrugated gray wares also figured prominently in Varien's (1997*1, 1999*1) study of sedentism and mobility in the Sand Canyon locality. Glowacki and others included sherds from Castle Rock in their studies of local pottery production and exchange (Glowacki 1995*1; Glowacki et al. 1995*1, 1997*1, 1998*1; Thurs et al. 1996*1). Fratt (1997*1) analyzed manos from Castle Rock and several other sites in southwestern Colorado. Driver (1996*1, 1997*1) and Munro (1994*1) studied faunal remains from Castle Rock and other sites in the Sand Canyon locality.

Organization and Use of This Report

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This report is organized into sections and subsections, a list of which can be accessed by clicking on the expanded table of contents at the top of the chapter. Clicking on a selection in the table of contents will allow you to go directly to the section you are interested in without having to scroll through the entire chapter. When you click on a link to a table, figure, or reference in the text, a new browser window will open in which the selected information will be displayed. You can move back and forth between the chapter text and the data window by keeping both windows open, overlapping them (i.e., not viewing them full screen), and selecting one or the other window. The data window will be updated each time a link for a table, figure, or reference is selected in the narrative text window; the text window will maintain your place in the longer document. Database Maps open in the same window as this report, and you will need to use your back button to return to this chapter. In many subsections, contextual information taken from the field context database is given along with analysis information for selected artifacts. Explanations of field context information can be found in the on-line field manual.

Pottery
Unmodified Sherds

¹⁰
More than 40,000 pottery sherds, weighing more than 250 kg, were collected during excavations at Castle Rock Pueblo. All of these were analyzed according to Crow Canyon's standard analysis procedures, which are described in the on-line laboratory manual. The following pages present several summaries of the basic sherd data and discuss several issues related to the comparison of sherd data from Castle Rock with data from other sites.

Total Inventory

By Ware and Type

¹¹
The sherds collected from Castle Rock are tabulated in Table 1 according to pottery type (for type definitions, see the on-line laboratory manual). The list of pottery types is arranged according to the more general ware to which each type belongs. Unknown white, gray, and red ware sherds are listed separately because such sherds may or may not represent local wares. Results are given by count and by weight in grams, and the percentage of each pottery type in the collection, by count and weight, is also given. Pierce and Varien (1999*1) discuss the relative merits of counts vs. weights as measures of abundance.

¹²
The table shows that percentages of various pottery types can vary depending on whether counts or weights are used. This effect is especially clear for Mesa Verde Black-on-white, which is much more abundant by weight than by count. In contrast, the relative abundance of Pueblo III White Painted, a more general type used for sherds that do not exhibit diagnostic attributes of either McElmo or Mesa Verde black-on-white, is approximately equal by count and weight. Consistency in the relative frequency of a type for both count and weight probably indicates that sherds assigned to that type tended to be of average size for the collection overall. Greater relative frequency by count indicates that sherds assigned to that type were smaller than average, and greater frequency by weight indicates that sherds assigned to that type were larger than average. That sherds identified as Mesa Verde Black-on-white tend to be larger than average is expected, since the classification of local white ware sherds to traditional types relies heavily on the identification of specific painted designs, which are often difficult to identify on small sherds.

Dating the Occupation of Castle Rock Pueblo Using Assemblage Type Data

¹³
Wilson and Blinman (1999*1) defined pottery assemblage profiles that characterize Mesa Verde-region ancestral Puebloan sites dating to various time periods between A.D. 575 and 1300. The pottery from Castle Rock Pueblo suggests that the ancestral Puebloan occupation at this site falls squarely into their A.D. 1225–1300 period. During this period, Mesa Verde Black-on-white was the dominant decorated white ware type, with only trace amounts of McElmo Black-on-white and Mancos Black-on-white. Mesa Verde Corrugated was the dominant gray ware type, and red wares were scarce. The pottery assemblage from Castle Rock follows this idealized assemblage exactly, regardless of the measure of abundance used, and it corresponds with the period of occupation suggested by tree-ring and architectural data. Thus, the pottery assemblage from Castle Rock is indicative of a single occupation dating between A.D. 1225 and 1300. There is no pottery evidence of an earlier occupation.

By Ware and Form

¹⁴
All sherds collected from Castle Rock were assigned to one of four basic form categories: bowl, jar, other, and unknown. Total counts, weights in grams, and percentages by count and weight for these four form categories are presented in Table 2 by ware category. Unlike the type percentages, the percentages of various ware-form combinations are fairly consistent for both counts and weights. This pattern suggests that sherd size does not significantly affect the ability of analysts to assign sherds to wares and forms. Consistency in the percentages of ware-form combinations by count and weight is most likely due to relatively consistent sherd sizes across wares and forms in the Castle Rock sherd assemblage. As a result, intrasite comparisons can be made using either counts or weights. Notice, however, that weight is the superior measure for comparing the relative frequencies of wares and forms across sites, because sherd sizes can vary systematically across depositional contexts, owing to a number of depositional and postdepositional processes.

¹⁵
These ware-form combinations are also found in roughly the same proportions in other Pueblo III sites in the Sand Canyon locality that have been interpreted as permanent, year-round habitations (Pierce and Varien 1999*1). This suggests that the ware-form characteristics of the Castle Rock sherd assemblage resulted from a set of domestic activities that produced sherds of various wares and forms at a relatively consistent rate across sites. This inference is supported by the fact that nonhabitation sites do not possess the same proportions of these ware-form categories in their sherd assemblages. For example, the sherd assemblage from Site 5MT12086, a reservoir in Woods Canyon approximately 20 km from Castle Rock, is dominated by white ware jars and contains few corrugated jars or white ware bowls (Wilshusen et al. 1997*1:Table 1). Obviously, the activities that occurred at the Woods Canyon reservoir led to different patterns of sherd deposition than are typical of habitation sites, including Castle Rock Pueblo.

By Type and Finish

¹⁶
Two kinds of paint are identifiable on decorated Mesa Verde White Ware. Mineral paint derives from ground iron, manganese, or copper-rich rock that is held in liquid suspension. Carbon paint is believed to derive from the condensed extract of certain plants, such as Rocky Mountain beeweed (Cleome serrulata) and tansy mustard (Descurainia richardsonii). In the Sand Canyon locality, mineral paint is most common in sherd collections dating to before A.D. 1150, whereas carbon paint dominates in later periods. Mineral-painted white ware, however, continues to be common in thirteenth-century sites located northwest of the Sand Canyon locality, in the bean-field and canyon country along the Utah-Colorado border west of Pleasant View, Colorado (Wilson 1991*1).

¹⁷
Table 3 presents counts and weights of white ware sherds assigned to various type and finish categories. The row percentages show the relative abundance of carbon and mineral paint within each pottery type, and the column percentages show the relative abundance of each white ware type among all white wares, regardless of paint type. The table shows that very few mineral-painted sherds were collected from Castle Rock Pueblo. Only five of the 38 mineral-painted sherds in the Castle Rock assemblage were classified as Mesa Verde Black-on-white, a definite late Pueblo III type. Whether the vessels that produced these sherds were imported from areas where potters more commonly used mineral paints, or whether a few Castle Rock potters used mineral paint, is unknown. The remaining mineral-painted sherds were all classified as potentially earlier pottery types (Pueblo III White Painted and Late White Painted) or definitely earlier ones (McElmo Black-on-white, Mancos Black-on-white, Pueblo II White Painted, and Early White Painted). Although their presence could be explained by one of the scenarios described above, it is also possible that these sherds are from "heirloom vessels" that lasted an especially long time before breaking.

Rim Sherds
By Ware and Type

¹⁸
Rim sherds may provide a better indication of type frequencies among the vessels used during an occupation because rim sherds usually preserve more diagnostic attributes of pottery types than do body sherds, and therefore they tend to be classified more precisely than body sherds. Table 4 presents counts and weights of rim sherds in the Castle Rock sherd assemblage by ware and type. The relative frequency of rim sherds assigned to each type is given as a percentage of all rim sherds by count and weight. The relative frequency of specific, named types is clearly much higher among the rim sherds alone than in the entire sherd assemblage, but the basic typological assemblage profile, with Mesa Verde Corrugated the dominant gray ware type, Mesa Verde Black-on-white the dominant white ware type, and red wares quite rare, is still apparent.

¹⁹
As was the case for the overall sherd assemblage, significant differences in the relative frequencies of different types by count and weight probably relate to the average sizes of rim sherds assigned to each type. As examples, Mesa Verde Black-on-white and Mesa Verde Corrugated are nearly twice as common by weight as by count, whereas Pueblo III White Painted and Indeterminate Local Corrugated Gray are nearly twice as common by count as by weight. These patterns indicate that rim sherds assigned to specific traditional types tend to be larger than average, whereas rim sherds assigned to generic types tend to be smaller than average. Nevertheless, the higher frequencies of specific types among the rim sherds indicates that rims were assigned to these specific types more often than body sherds were.

By Ware and Form

²⁰
Rim sherds can often be assigned to more specific form classes than can body sherds, and when it was apparent during analysis that a rim sherd came from a ladle, canteen, mug, or kiva/seed jar, this was recorded in a "comments" field. Ladle rims curve more tightly than bowl rims and possess distinctive use wear on the outside edge of the rim or evidence of a handle attachment. Canteen rims are small jar rims with very tight curvature. Mug rims are square and upright, are seldom everted, usually possess intricate painted decorations on their exteriors, and sometimes preserve evidence of a handle attachment near the rim. Kiva and seed jars are slightly larger than canteens, do not have necks, and, in the case of kiva jars, have a distinctive lip that is designed to hold a lid in place.

²¹
Table 5 summarizes the wares and forms of rim sherds in the Castle Rock assemblage by count and weight. The more specific vessel forms of kiva jar, seed jar, ladle, and mug are split out in this table on the basis of information recorded in the comments field of the pottery data file. It is assumed in this table that white ware jar rims for which no additional comments were recorded in the file are from large storage jars, or ollas. As was the case for the entire sherd assemblage, the three most common vessel forms represented among the rim sherds are corrugated jars, white ware jars, and white ware bowls. The relative frequencies of these three forms, however, are strikingly different when rim sherds alone are considered. White ware bowls are by far the most common ware-form combination among rim sherds only, whereas corrugated jars are by far the most common among all sherds.

²²
These differences relate to the typical circumferences of rims in the original vessels of these various ware-form combinations and to differences in the relative numbers of rim and body sherds produced by vessels of different sizes. White ware bowls are open forms with large rim circumferences; when they break, they produce numerous rim sherds and a relatively high ratio of rim to body sherds. Corrugated and white ware jars are closed forms with small rim circumferences that produce far fewer rim sherds per vessel than do white ware bowls. As a result, the best way to estimate the relative number of vessels of different ware-form classes in a pottery assemblage is to compare the total degrees of arc subtended by the rim sherds of various ware-form classes. Such data were considered by Pierce and Varien (1999*1) in their study of the Sand Canyon locality Site Testing Program assemblages, including the testing sample from Castle Rock. They found that raw counts of rim sherds, though less precise than degree-of-arc measurements, nevertheless gave a closer approximation of the relative numbers of vessel ware-form classes than did raw counts of all sherds. Judging from this finding, it appears that white ware bowls were the most common vessel form used at Castle Rock, followed by corrugated jars and then white ware jars and white ware ladles. Canteens, mugs, and kiva/seed jars were all relatively rare.

²³
As is the case for the overall assemblage, the rim sherds show relatively little variation between the percentages based on counts and those based on weights when classified in terms of ware-form combinations. This suggests that sherd size does not significantly affect the ability of analysts to assign rim sherds to wares and forms.

Counts by White Ware Type and Form

²⁴
Table 6 summarizes the forms of rim sherds assigned to various white ware types. Counts alone are considered in the upper register of this table, and the lower register gives relative frequencies across types for each form class. The total and relative frequency by count of each type for the overall white ware rim sherd assemblage is given in the far right column of the table. The table illustrates that significant variation exists in type frequencies across form classes. As examples, Late White Unpainted sherds are much more common among jar rims than among bowl and ladle rims, and McElmo Black-on-white, a type common in pottery assemblages dating between A.D. 1140 and 1225 (Wilson and Blinman 1999*1), is much more common among ladle rims than among bowl rims.

²⁵
The elevated frequency of Late White Unpainted sherds among jar rims probably relates to differences in the decorative treatment of jars vs. bowls and ladles. The primary decorative field of white ware jars was the upper half of the jar body, and the necks and rims of many such jars were left unpainted. Although some white ware bowls and ladles, too, were left undecorated, in most cases the rims and interiors of such vessels were intricately painted, leading to a lower frequency of unpainted bowl and ladle rim sherds.

²⁶
One possible explanation for the elevated frequency of McElmo Black-on-white among ladle rims derives from ethnographic studies which indicate that vessels of different forms and uses have varying use lives (Varien and Mills 1997*1). If the vessel forms used by the inhabitants of Castle Rock also had varying use lives, then vessel forms with longer use lives might have tended to be older by the time they were broken and discarded than were vessel forms with shorter use lives, and this might be reflected in a higher percentage of earlier types among rim sherds of longer-lived vessel forms. Since the cup of a ladle is much smaller and sturdier than that of a bowl, it is likely that ladles had longer use lives than bowls. If this was the case, then a higher frequency of McElmo Black-on-white ladle rims might relate to differences in the use lives of these two form classes.

²⁷
A second possible explanation relates to the details of pottery type definitions. McElmo Black-on-white designs are usually seen as being simpler than Mesa Verde Black-on-white designs, and since ladle interiors are much smaller than bowl interiors, it might have been difficult to execute a more complex Mesa Verde Black-on-white design on a ladle interior. It is therefore possible that some ladle rims were classified into an earlier style, not because ladles lasted longer before breaking, but because their designs were necessarily simpler than those of larger bowls.

Weights by White Ware Type and Form

²⁸
Table 7 presents the total weight of white ware rim sherds assigned to various types and forms. Percentages by weight of white ware types are given by form, as are the mean weights of rim sherds assigned to various type-form combinations. The total and relative frequency by weight of each type within the white ware rim sherd assemblage is given in the far right column of the table.

²⁹
The first two registers present the sum of weights and the column percentages by weight for rim sherds assigned to each form category. They illustrate some of the same patterns discussed for the type-form data by count. There is an elevated frequency of Late White Unpainted sherds among the jar rims and an elevated frequency of McElmo Black-on-white among the ladle rims. And as is the case for the overall sherd assemblage, there is significant variation in type frequencies depending on whether counts or weights are used (compare this table with Table 6). It is likely that the effects of sherd size on the typing of rim sherds are responsible for these differences, as was discussed for the entire sherd assemblage. The third register presents the mean weights of white ware rim sherds assigned to various type-form combinations.

Size Distributions for White Ware Bowl Rim Sherds

³⁰
Table 8 summarizes the number of white ware bowl rim sherds assigned to different types, along with means and standard deviations of their weights in grams. These data support the notion that sherd size significantly affects the ability of analysts to assign sherds to specific named types. It has already been shown that Mesa Verde Black-on-white sherds are consistently more abundant by weight than by count. This table shows that for white ware bowls, rim sherds classified as Mesa Verde Black-on-white are larger on average than rim sherds assigned to more generic types, such as Pueblo III White Painted and Late White Painted. These data indicate that larger sherds are generally easier to type than smaller ones.

³¹
It is also interesting that rim sherds assigned to the earlier McElmo Black-on-white and Mancos Black-on-white types are smaller on average than rim sherds classified as Mesa Verde Black-on-white. It is possible that rim sherds assigned to earlier types are smaller because they really are older, were deposited earlier in the occupation of Castle Rock, and had more opportunity to be fragmented before being safely buried. Alternatively, this relationship might represent an analytical bias in which smaller sherds had a greater likelihood of being classified as earlier types than did larger sherds. It is also possible that earlier types are easier to identify from small sherds than are later types.

By Form and Finish

³²
Table 9 presents total counts and weights of white ware rim sherds assigned to various form-finish combinations. Percentages of paint types within each form class are given in the second register, along with the percentages of forms across all decorated white ware rim sherds in the assemblage. As is apparent in the entire sherd assemblage, mineral paint is rare among the decorated rim sherds at Castle Rock.

Summary of Pottery Sherd Analysis

³³
The pottery sherd assemblage from Castle Rock Pueblo mirrors the tree-ring data in arguing that Castle Rock was inhabited between A.D. 1225 and 1300. There is no evidence in the pottery assemblage of an earlier occupation. The decorated sherds in the assemblage are dominated by carbon paint, to the near exclusion of mineral paint. The most common vessels used by the inhabitants of Castle Rock were white ware bowls, followed by corrugated jars, white ware jars, and white ware ladles. Canteens, mugs, and kiva/seed jars were all relatively rare. The wares and forms represented in the sherd assemblage occur in roughly the same proportions as in other Pueblo III habitation sites in the Sand Canyon locality.

³⁴
The summaries of Castle Rock pottery sherd data presented in paragraphs 10–32 have raised several important issues regarding the effects of ancient activities, of depositional and postdepositional processes, and of analytical biases on pottery sherd data. These issues have implications for comparisons of sherd data across sites. Sherd size does not significantly affect pottery ware or form data, making weight a suitable measure of abundance for ware-form classes across assemblages with different inherent sherd size distributions. Sherd size, however, does exert a significant effect on pottery type data, and this is a cause for concern. Because larger white ware sherds are more easily and accurately assigned to specific traditional types, it may be necessary to restrict comparisons of assemblages from different depositional environments to sherds that are larger than a certain minimal size. The 1/4-inch screens used in the field to collect the Castle Rock assemblage appear to have been too fine to control for sherd size effects in typing.

³⁵
Type frequency data can also vary widely owing to variation in the inherent mix of activities that occurred at a site. Different vessel forms were decorated differently, and as a result, an assemblage dominated by white ware jars will produce many more Late White Unpainted sherds than an assemblage dominated by white ware bowls, for example. Therefore, pottery type data for individual form classes should be considered separately. Comparing type data for each form class separately also controls for the possibility of varying use lives for different vessel forms, which could also have an effect on type frequencies.

Modified and Shaped Sherds
Inventory by Type

³⁶
A number of sherds that had been modified or shaped after their parent vessels broke were collected during the Castle Rock excavations. Table 10 summarizes the types to which such sherds were assigned, by count and by weight, along with relative frequencies of different types by count and weight. Modified sherds possess at least one abraded edge. Shaped sherds have edges that were flaked, ground, or both to make a specific shape. Some larger shaped sherds may be pottery fragments that were used as containers or as pottery molding trays called pukis. Perforated sherds with shaped edges were classified as sherd pendants and are discussed in paragraph 132. Sherds with shaped edges but lacking a perforation, such as disks, triangles, and rectangles, were classified as shaped sherds and are included here. These shaped sherds may have been pendant blanks, gaming pieces, or other nonutilitarian items.

³⁷
The table shows that relative to the overall sherd assemblage, modified corrugated sherds are underrepresented but tend to be larger than the other modified or shaped sherds. Corrugated sherds are not well suited for use as pottery scrapers because they have rough surfaces, coarse paste, and large temper inclusions that make it difficult to create a smooth scraping surface. Several complete examples of corrugated sherd containers, however, have been found in excavations at Sand Canyon Pueblo. White ware and red ware sherds are overrepresented relative to the entire sherd assemblage. Red ware is also overrepresented among the sherd pendants, suggesting that the modified red ware sherds were pendant blanks and that the inhabitants of Castle Rock preferred to make pendants using sherds from rare or unusual pottery vessels. Most modified and shaped sherds are of white ware and probably represent portions of pottery scrapers, gaming pieces, or pendant blanks.

Next (paragraphs 38–90).

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