House Wall and Clay Floor

On Thursday we discovered evidence that the curious clay layer may have served as floors for dwellings.  A careful examination of the clay floor exposed in unit 498N 512E revealed an arc of post molds running along the edge of the floor.  These posts measure about 5 to 7 cm (1.5 to 2.5 inches) in diameter and penetrate through the floor.  The white dots in the image below mark these post molds.  The red areas are heat-oxidized areas of the floor; most likely places where fires were made.  The dark soil area on the left (west) represent where shallow pit features were dug, parts of which cut out small sections of the floor.  We are not sure what these pits were used for, but they contain significant amounts of animal bone and some fire-cracked rock.

One final feature of note was found in the southeast corner of the excavation unit (lower right).  This small, dark, shallow pit cut through a burned area of the floor, which tells us that it definitely post-dates the creation--and maybe occupation--of the dwelling that was built here four millennium ago.

Finding the Clay Surface

This past Thursday, we found the base of the midden in unit 500N 512E at about 55 cm bd.  In the process, we uncovered the unusual yellow clay layer first discovered in 2008.  At that time we thought this clay was the natural subsoil that underlies the midden across the site.  Instead, it turned out to be a cultural surface resulting from the human occupation of the site.  We know this because beneath the yellow clay is an organic soil stratum which contains prehistoric cultural material.  We are not yet sure how this clay layer was created.  It may be the backdirt from digging deep pits dug nearby that penetrated the natural sandy clay subsoil.  But it may instead represent a deliberately created floor or working surface.  If so, then its presence shows that the Late Archaic inhabitants of this site took time to modify their settlement in a way that would last some time.  The image below shows the clay stratum and a large pit feature that appears to cut through this layer.

Next door, in unit 498N 512E, the dark organic midden soil was still being encountered.  Deer bone and antler, and carbonized nutshells are being found in abundance.  Among the finds was the base of a large flint drill.  On Friday, a drill tip was found near where the base turned up.  Not surprisingly, the two fragments fit together to form a long tool that measures about 12 cm (4.5 in) in length as shown below.  This exceptional tool was most likely complete when lost or stored at the Late Archaic campsite.

Tracing the Midden

Last week's rains set us back a bit, but this week has been relatively dry, and we have accomplished quite a bit.   Yesterday, we completed our shovel-test survey of the site with the help of youngsters in a Museum Archaeology program.  Eight eager students busily shoveled, troweled, and screened until the job was complete. 

We found few artifacts and virtually no midden deposits, but this was ok, at least for me, since we expected to be working at the very southern edge of the site.  So, the lack of discoveries was exactly what I expected.  The information from this survey will be very useful for understanding the diversity and locations of activities carried out by the prehistoric inhabitants of Burrell Orchard.   With the measurements taken during the excavation of each shovel-test unit, I was able to construct a map showing the depths of the midden deposits across the site.  As shown below, this map reveals a slightly curving distribution of deep deposits, some extending to more than 80 cm beneath the surface. 

As it happens, our current excavation units are situated within some of the deepest deposits on the site.  In future seasons, we will test areas of more shallow midden to better understand what was going on in places of less intense activities.