The winter weather here is really unbelievable: for the third straight Friday we had a nice, sunny day in the field (cooler than last week -- mid-50's -- but still great weather to work outdoors). One downside to the warm winters here is that you can encounter ticks and mosquitoes even in January. That's a fair price to pay, however, for the ability to do archaeology all through the year without employing heroic measures like temporary structures and heaters.
We got lucky with the weather last Friday, as it rained pretty heavily on Saturday and Sunday. So the first thing we had to do this morning was bail out the units. Everyone needs to learn how to bail out units.
We got lucky with the weather last Friday, as it rained pretty heavily on Saturday and Sunday. So the first thing we had to do this morning was bail out the units. Everyone needs to learn how to bail out units.
Bailing using the bucket line method. We only had seven square meters open by the end of the day last Friday, so we didn't have much volume to deal with. As this block gets deeper I may look into acquiring a pump. View is from the north edge of the block facing south.
Excavation of the block units continued with completion of the first level, ending at 40 cm below datum (cmbd) in Units 4, 5, and 6. The Unit 5 crew had significantly more roots to deal with, so their Level 1 took longer (they wrapped it up by the end of the day today). In Units 4 and 6, I had them excavate Level 2 (40-50 cmbd) as an arbitrary 10 cm level across the whole 2m x 2m unit simultaneously. The point of having them excavate Level 1 in 1m x 1m quadrants was to give everyone some repetitions taking elevations, excavating, making bags, and filling out forms. I felt like they had grasped the basic methods and procedures after the first level, so it was appropriate to have them try their hands at a 2 x 2. Unit 6 was done with Level 2 by the end of the day; Unit 4 still has a final trim and clean-up to go.
Excavations in progress in the block. Level 1 nears completion in Unit 5 (to the left); Level 2 in progress in Units 4 and 6.
The second levels in the block units, ending at 50 cmbd, will still end within the upper sediment zone at the site. We now know this is a plowzone, thanks to work going on in the "downstairs" part of the site.
After Jim Legg and one of the students finished up what little remained of Unit 8 first thing in the morning, we used the total station to locate a couple of grid points "upstairs" to establish the E 1000 line. We resectioned off the two permanent (concrete and rebar) datums that I established last May when I started work on the profile. (In survey work, "resectioning" is when you shoot two known points to figure out the location of an unknown point -- where the instrument is set up. Once the computer in the total station calculates the position and orientation of the instrument with respect to the site grid, you can then shoot additional unknown points. Doing this is often much more convenient then setting up over a known point and shooting to a backsight, as you can set up anywhere as long as you can see two known points.)
After Jim Legg and one of the students finished up what little remained of Unit 8 first thing in the morning, we used the total station to locate a couple of grid points "upstairs" to establish the E 1000 line. We resectioned off the two permanent (concrete and rebar) datums that I established last May when I started work on the profile. (In survey work, "resectioning" is when you shoot two known points to figure out the location of an unknown point -- where the instrument is set up. Once the computer in the total station calculates the position and orientation of the instrument with respect to the site grid, you can then shoot additional unknown points. Doing this is often much more convenient then setting up over a known point and shooting to a backsight, as you can set up anywhere as long as you can see two known points.)
Total data station (TDS) set up to resection from known points "downstairs" then shoot to locate desired points "upstairs."
We placed spikes at 999 N / 1000 E and 1006 N / 1000 E and laid out Unit 9 as a 1m x 3m unit, the excavation of which would continue the north-south profile line that I started with the excavation of Units 1 and 2.
Updated unit map showing the location of Unit 9.
With the 1000 E profile line laid out, Jim Legg and his crew could start excavating Unit 9. They started this from both the top and the side, first cutting the walls of the unit from above and then using a shovel and dustpan to come in from the profile wall itself. The strategy was to remove the first sediment zone as a natural level (using the existing profile as a guide), paying particular attention to the interface between the upper zone and what was below it. In the profile, there is a darker zone visible immediately beneath first zone.
Removal of Level 1 of Unit 9 in progress. The pink string marks the 1000 E line. The black plastic in the foreground is covering the wooden covering I constructed to protect the portion of the profile exposed by the excavation of Units 1 and 2. The goal is to have 5m of profile wall on the same plane (with the exception of some irregularities present in the existing wall).
When Jim and his crew got to the base of the uppermost zone, it was apparent (as we suspected) that it is a plowzone. There are linear plow scars running across the unit. This diagnosis of the uppermost zone as a plowzone is consistent with the mixture of historic and prehistoric artifacts we've been finding in Levels 1 and 2 of the block units.
Plow scars visible at interface of Zones 1 and 2 in Unit 9. In this case, the lighter sediment is the plowzone.
Exposing the base of the plowzone in Unit 9 provided a good opportunity to show the students what we're looking for in a transition -- the color change is the reverse of what you normally see, as the sub-plowzone sediment (at least in the profile) is darker than the plowzone. I continue to suspect that there may be an intact Mississippian/Woodland component immediately below the plowzone. We've been getting a fair number of prehistoric sherds in the upper levels of the block units and in the plowzone in Unit 9. Hopefully we'll know more by the end of the day next Friday. Stay tuned!
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