1999 Field Season: Day 13

July 7, 1999

Today, we began the lift at site B8-1, in which we removed the fossils and stone tools found.

The lift begins by setting the transit up on a datum point and shooting back to another datum to make sure that the instrument is reading correctly. Down in the trench, while the transit is being oriented, the site leaders go through all of the artifacts and fossils, deciding in what order to gently lift them from the sediment. Also, they must appraise the condition of the fossils and determine whether or not they can be lifted as is, or if they need to be encased in a protective sleeve of plaster. This preparative portion of the lift is much like establishing a game plan.

The lift team at B8-1.

Each person in the lifting process has a specific and narrowly defined job to perform for each item taken from the site. We have it down to a routine. One person records the general information about each specimen in the site data notebook. This information tells us the specimen number, what kind of specimen it is (usually "stone" or "bone," but if the object is distinctive it may include a couple word description) and any dip and orientation of the object that is present. The recorder then picks the object up (if possible).

While the general information is being recorded, a transit team member places a prism pole (a pole that is scaled to the exact height of the transit with a reflective prism on the top) where the object was and calls the specimen number to the transit operators. They take a reading of the position of the object and record it in the transit data notebook.

The transit crew takes a position reading for a fossil at the site.

The object then gets handed to another person who wraps it in tissue, and places it in a plastic bag with the site number, the year of excavation, and the specimen number written on the top. At the end of it all, we have a large bowl full of fossils and artifacts, each in their own labeled bag ready to be transported back to camp. It sounds a bit complicated, but once you get going, the process becomes an assembly line, and you can go through a large number of objects rather quickly.

A bowl of bones and stones.

Any fossil that is too fragmented to safely be removed by hand is encased in plaster. We use the same stuff doctors use to make casts (and in a way, we are also trying to keep parts of the same bone from moving around). First, a layer of preservative is applied to the surface of the fossil, and after it is allowed to dry, we apply seven or eight layers of toilet paper to the fossil. This is so the plaster from the cast will not stick to the fossil, and possibly pull tiny flakes of bone away when we remove it. The toilet paper is then wetted down so it conforms to the shape of the fossil, and so the plaster will stick to it better. Then comes the plaster. We try to apply several layers, being sure that the cast fits to the surface of the fossil as well as possible. Since you can only apply the cast to the side of the fossil that is exposed, you must wait until the cast is dry, cut away under the fossil, carefully flip it over, and then repeat the process. At this point comes the unenviable task of having to carry this heavy mass of fossil, rock and plaster back to the vehicle.

Applying a plaster cast to the femur at B8-1.

When we are back in camp, the transit team sits down with their transit notebook, in which they recorded the position data, and and copy these data into the the site data notebook. This way, all of the information about each object recovered from the site is recorded in one place that is reserved for this particular site. The next step is to enter all of the data into a computer database, but that will wait until we are back at the museum.

Muthengi Kioko carries one of the fossils back to the vehicle.