June 30, 2004
The search for context leads us to excavate every site with great care and to recover every little scrap of evidence that can help us interpret each site. This is why Jenny, with the help of Lynn, Amanda and Jessica, has spent the past few days examining the sediment from the hominin fossil site, AD5/7-1. She's looking for fossils of microfauna. Microfauna are the very small animals, the little rodents, amphibians, and invertebrates that die and leave fossils in a site just like larger animals do. Yet their bones are so small that it's almost impossible to see them when we first excavate. Last year, we saved all of the sediment excavated from the hominin discovery site; and then it was washed in water and put through tiny sieves, and saved in bags again waiting for Jenny's return to Olorgesailie.
Jenny looks through those bags carefully, one scoop of washed sediment at a time, sometimes with the help of a microscope. Once she finds fossils, Jenny will try to identify the kind of animal they came from. Because different kinds of animals prefer different environments, Jenny can get an idea whether the area in which the hominin died was wet or dry, or what kind of vegetation grew there. This information is just one more piece of the puzzle in figuring out the setting in which the hominin lived.
Jenny's examination of the sediments from AD5/7-1 has so far found mostly fish bones, probably from catfish from ponds that once existed near the site, and also frog bones and small rodent bones. One of the rodent teeth is from the genus Otomys, which is the group of species known as African swamp rats. Jenny's finds imply that there was a pond or marsh near the lava ridge along which the hominin died before it was buried by natural sediment and turned into a fossil.
I returned from Nairobi in the afternoon. It caused quite a fuss by our team that I arrived in a new truck that I bought last year for our work. As you can see in the photos, the entire team was very curious about it. After lunch, Lynn and Amanda went out to Site 15, the butchery site, where they had their first experiences digging. Both enjoyed it, though both developed a few scratches and blisters - something that Lynn considered her first badges as "a real archeologist." She also says, "Hi, Mom!" It was a good day to learn how to dig, as the team was digging slowly but hadn't quite reached the sediment with archeological material in it. Tomorrow, hopefully, they'll reach the layer with fossils and tools, and everyone will have to be especially careful.