Figure 1. Plot of contexts along CA Dimensions 1 and 2. Time runs from right to left.

Figure 2. Plot of MCD Types along CA Dimensions 1 and 2. Note that later types are on the left.

Figure 3. CA Dimension 1 scores plotted against Mean Ceramic Dates.

Figure 4. Histogram of ceramics from the Project 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.

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 MCD 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 MCD-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 one assemblages are generally lower stratigraphically and include one deposit within the cellar (F09) of MRS 2 as well as layers cut by (SG13) and sealing  (SG02) the feature. Phase two assemblages come from two important SGs, a garden fenceline deposit (SG27) and a clay layer with greenstone (SG16). The latter, SG16, although stratigraphically between two Phase one fills, contains only creamware and chinese porclain, suggesting it too may be a phase one assemblage. Its small sample, with no mid 18th century types, may have set it off from the other phase one assemblages in the CA. Phases three and four have increasingly substantial amounts of post-Jefferson material, as indicated by the late MCD, TPQ, and TPQp90.