Building n (Wash House) & 1809 Stone House
Intra-Site Chronologies
Figure 1. Plot of contexts along CA Dimensions 1 and 2. Time runs from right to left.
Figure 2. Plot of Ware Types along CA Dimensions 1 and 2.
Figure 3. CA Dimension 1 scores plotted against Mean Ceramic Dates.
Figure 4. CA Dimension 1 scores plotted against BLUE MCDs.
Figure 5. Histogram of ceramic counts plotted along CA Dimension 1. The lines indicate DAACS phase divisions.
We perform a standard set of analyses to infer intra-site chronologies for the sites included in the Archive. Using them, we have assigned most excavated contexts at each site to a set of site-specific phases. The use of common analytical methods is designed to increase comparability among phases at different sites. The methods and the phase assignments they produced are summarized below. For some sites, the original excavators developed intra-site chronologies and, where these exist, they are included on the Background page for the site. DAACS encourages users of Archive data to help explore improvements.
DAACS Seriation Method
This page summarizes the frequency-seriation based chronology we developed for the 1809 Stone House project (see Neiman, Galle, and Wheeler 2003 for technical details).
As with other sites in the Archive, the seriation chronology for the 1809 Stone House project was derived from ceramic assemblages aggregated at the level of contexts and stratigraphic groups, and not at the level of features. This is because most contexts and stratigraphic groups on the site were not parts of features. For the relatively few cases where seriated contexts and stratigraphic groups were parts of features, the relevant feature numbers and descriptions are included in the seriation chronology table below. A seriation using MCD-types did not produce a successful chronology for the site. Thus, the seriation chronology presented here is the result of a correspondence analysis of ware-type frequencies in each stratigraphic group and each individual context that had no stratigraphic group assignment (Figures 1 and 2). Not all contexts have stratigraphic group assignments.
To reduce the noise introduced by sampling error, only ceramic assemblages with more than 5 sherds and more than two ceramic type from individuals excavated contexts and from stratigraphic groups were included. The results produced a strong correlation between Dimension 1 scores and MCDs (Figure 3). The correlation is even stronger for Dimension 1 scores and BLUE MCDs, which weights ware types with shorter manufacturing spans (Figure 4) (see Neiman and Smith 2005 for details). Based on the dips in ceramic counts observed in a histogram of Dimension 1, we divided the site into three phases (Figure 5). An additional phase (P04) was created from a group of three SGs set apart along Dimensions 1 and 2. Phase four assemblages appear to be mixed deposits with both early and late material.
Building n & 1809 Stone House Site Phases
Phases are groups of assemblages that have similar correspondence-analysis scores, similar MCDs, or both, and are therefore inferred to be broadly contemporary. Phases have a P-prefix that precedes the phase number (e.g. P01 equals Phase 1).
Mean ceramic dates for the site-specific phases are given in the table below. The table also includes two estimates of the ceramic TPQ for each phase. The first TPQ estimate is the usual one – the maximum beginning manufacturing date among all the Ware types in the assemblage. The second estimate -- TPQp90 -- is the 90th percentile of the beginning manufacturing dates among all the sherds in the assemblage, based on their Ware types. This TPQ estimate is more robust against excavation errors and taphonomic processes that might have introduces a few anomalously late sherds in an assemblage.
| Phase | MCD | TPQ | TPQp90 | Total Count |
|---|---|---|---|---|
| P01 | 1784 | 1762 | 1762 | 13 |
| P02 | 1786 | 1820 | 1762 | 532 |
| P03 | 1798 | 1820 | 1775 | 1498 |
| P04 | 1815 | 1840 | 1820 | 546 |
Phase one is a small assemblage from F18, described as a pit or tree hole with the same fill as the layer above it (SG09). Phase two encompasses for the most part what Kelso and his team interpreted as the "Occupation Zone" and is found in the units to exterior to the Stone House underlying the stratigraphic layer containing MRS-5 deposits (SG10). Phase three is comprised of assemblages from contexts associated with MRS-5 as well as deposts associated with the construction of the Stone House. Phase four consists of later period ceramics and may represent mixed and disturbed deposits on or near the modern surface. No deposits could be linked to the Building n described by Jefferson in 1796.
A Seriation Chronology for the Building n & 1809 Stone House Site
The following table presents a seriation chronology for the 1809 Stone House project. We use the indefinite article to signify that it is not the only chronology possible, nor the best. We encourage users of Archive data to help explore improvements.
The stratigraphic relationships among stratigraphic groups and unassigned contexts are summarized in the Harris Matrix for the site. Phase assignments from the seriation are shown on the Harris Matrix in color, facilitating comparison of the seriation chronology and the stratigraphic chronology of the site.
