At the Community Archaeology dig I do almost all the backdirt screening. We screen all the dirt to make sure no one misses any artifacts and it is important that we know the location and level for each bucket of dirt. We use colored buckets to keep track of where the buckets come from - each excavator uses a particular color combination. So say if I find a flake in the dirt from the yellow bucket then I know it came from 'Gabe's square in the corner'.
I think screening is the most important job on an archaeological excavation and I only let the best hands do it, and I try and do it all myself. The point of screening is to provide consistency between squares - so if some people are better at it than others then you have lost consistency. Suddenly some squares have more artifacts than others not because it was that way in reality but because one screener was better than another.
Also since I am doing all the screening I effectively know what is going on in every single person's square. So if, say I see the color change from brown to black in one person's unit, then I know they might have changed levels - I can see and feel what everyone is excavating. Our backdirt pile is also right next to the excavation so I can physically watch from on high what everyone is doing too.
Another big advantage of centralized screening is that it speeds up the dig and keeps foot traffic across the excavation to a minimum. In the past when I have visited other digs there is usually a big backup at the screens. I have also been at digs where they have the least experienced people on the screens. I always wonder how they expect the inexperienced to find the rare and subtle artifacts that inevitably end up in the screen.
I also love screening at the beginning of the dig because people don't have an eye for artifacts yet and I get to find all sorts of cool things in the screen. However, by week three it seems that all I ever find is flakes or cobble scrap. No one misses much by the third week.
|Nick a paleontologist (really studies dinosaur bones) volunteered for a day and found some calcined bone some 66 to 100 million years younger (at least) than the bones he usually studies|
|Close up of the retouch on a flake tool|
|Nicole found this Piece Esquillee a 'bone wedge' used for splitting open bones|
|Katie and her lance tip - I am wondering if the serrations reduce suction in wounds and make it easier to both stab an animal and promotes bleeding|