Sorting sieved residues
Last Saturday, we were at Rewley House to sort the remains of the environmental samples from the Bartlemas dig after sieving and flotation (see previous blog). Rebecca Nicholson, Oxford Archaeology‘s Environmental Archaeology Manager, was there to show us how to do it. We each had to take four bags with residues of different sizes from the different sieves. It was very firmly impressed on us that WE MUST MAKE SURE THE SAMPLE NUMBERS AND CONTEXT NUMBERS MATCHED on all four bags. We were given helpful handouts and some general background info and forms to describe anything of interest in the residue. Tweezers and magnifying glasses were also provided as well as petri dishes to put interesting stuff in.
Starting with the largest size (>10mm), we tipped some of the bag into a finds tray and started to sort it. It was immediately obvious that most of my sample was small pieces of limestone rubble which was instantly discarded. However, there were some pieces of oyster shell and some small pieces of bone duly placed in small finds bags and CAREFULLY LABELLED. The form has a column for each size and lists , for example, different types of bone, burnt or worked flint, iron (Fe) and we had to enter the amount of each item according to a code. I had ‘abundant’ pieces of shell which was code 3 (25-100 items).
We plodded our way through the sorting, getting faster as we went along and got our eye in. Microscopes were set up and were extremely useful in showing which pieces were bone and which were belemnite (fossil). We all found shells of carniverous snails. (It was a burial ground.)
When we got to the smallest samples, there was a queue for the microscopes as we put a sample in a petri dish (Leigh wasn’t listening when this was mentioned and sorted the whole of his bag by hand and magnifying glass before Rebecca put him right!) and looked at it magnified. If there was nothing interesting in the samples, we discarded it. None of us found anything. ‘Nothing’ is good as it means anything of interest was captured in the flotation process. Finding seeds or charcoal means the flotation should really be done again.
Rebecca had some samples from the flotation which were fascinating and very complex. We were not let loose on sorting those! In order to make sense of what you are looking at, you need to able to identify it – a task which requires much more knowledge than any of us possesses.
We got through most of the samples during the day but there are a couple of big ones left so another day will have to be organised.