Group contexts are contexts that contain other contexts (usually spatial contexts, but group contexts can also contain other groups). Group contexts do not have their own spatial information or their own samples; all such information comes from the spatial contexts that they contain. Some group contexts will have stratigraphic relationships with surrounding deposits while others will not; this depends on the type of group context in question.
All features like walls, standing circular features, pavements, pits, etc., should receive group context numbers (rather than spatial context numbers) as soon as they are identified (soon after they are uncovered). There are a number of reasons for this. First, spatial contexts are closed between seasons; therefore, if a built feature like a wall is uncovered in one year and removed in another, the original (closed) spatial context would not be available for use in documenting the wall’s removal. Similarly, a feature may be subject to multiple actions or events during and after its original exposure (e.g., stones might become dislodged, it might receive conservation interventions, part of it might be removed, etc.). To enable documentation of such actions and events related to the same feature, we give features group context numbers. Finally, we give features group context numbers to facilitate the naming of features, their related parts, and subsequent references to them. It is important that the name of the feature remains consistent throughout the database, reports, etc., from season to season; a group context number allows for that name to stay consistent.
As mentioned above, you should assign a group context number to a built feature relatively soon after it is uncovered. If you have questions about when to do the, consult with a supervisor or leadership.
Remember that a group context for a feature should represent something that was a single entity in antiquity; spatial contexts that may represent parts of or actions on that feature primarily reflect the process of excavation. As such, stratigraphic relationships should be made between the group context and surrounding contexts, rather than between spatial contexts contained by the group and surrounding contexts. Take, for example, a wall (GC 5) that was covered by a large fill (SC 2) and cut by a pit in antiquity (SC 6) creating two wall fragments (SC 7 and 8). The stratigraphic relationships would be as follows:
SCs 7 and 8 are children of GC 5 (in the Group Children table)
GC 5 is earlier than, covered by SC 2 (in the Stratigraphy table)
GC 5 is earlier than, cut by SC 6 (also in the Stratigraphy table)
No stratigraphic relationships should exist between SCs 7 and 8 and SCs 2 and 6. However, spatial contexts within a group context may be given stratigraphic relationships with each other to clarify the construction of the feature.
Similarly, because a group context represents a single entity in antiquity, the group should only contain things that are thought to be contemporary. Take, for example, a circular feature (GC 6)—built of a bedrock cut (SC 4) and a stone wall (SC 5)—and its fills (SCs 1, 2, and 3). If the fills show no evidence of being contemporary with the use of the circular feature, then only the cut and the wall should be its children (SC 4 and SC 5 are children of GC 6) and the fills should have a stratigraphic relationship with the feature (GC 6 is earlier than, filled by SCs 1, 2, and 3). However, if there is clear evidence that the fills are contemporary with the use of the circular feature (e.g., they contain large amounts of carbonized grain indicating a silo), then they should be grouped with the feature (SCs 1, 2, 3, 4, and 5 are children of GC 6).
Interpretive Groupings #
The other main type of group context is interpretive. Interpretive group contexts are used to name features/events that transcend a single context, and to make it easy for both project members and non-project members to understand how contexts are related to each other both within and between excavation areas. Examples of interpretive groupings include: fills that were excavated separately, but in retrospect are likely the same deposit; the deposits that filled a feature, like a pit; and spaces (grouped walls) or buildings (grouped spaces).
Interpretive group contexts should only be opened after a great deal of consideration; you should not feel pressure to group fills or walls immediately upon their excavation. It is most likely that you would create interpretive group contexts when you are reconsidering stratigraphy and writing a report at the end of the season, or when excavation areas are being reconsidered in later seasons in light of new evidence.
Similarly, because interpretive group contexts are less “stable” than features (more subject to reinterpretation), they should not be given stratigraphic relationships. In the case of a space that groups four walls, the stratigraphic relationships of surrounding contexts should be made to the walls rather than the space.
NOTE: You do not need to create a group context to associate approximate contexts with the spatial contexts that contain them. Rather, simply indicate that the approximate context is “contemporary with, contained by” the spatial context in the stratigraphy table. Group contexts should only be used to group spatial contexts and other group contexts.
When to Open a Group Context #
It is rare that you will open a group context in the field; they should generally be opened in the lab after full consideration of why the group context is being made and what it will contain. Group contexts for features, however, should be opened shortly after they are discovered. (Remember: in order to name a wall or other feature that will remain in situ, give it a group context rather than a spatial context.) Interpretive group contexts will most likely be opened towards the end of the season, but can be opened after any amount of time, and in the off-season as well as during the field season.