July 4, 1999
Today is a well deserved day off for the crew, as we have put in a long week of hard work. We thought that a report of the state of our excavations would be appropriate.
At Site A11-10, overburden removal continues. We are expecting to hit the target layer soon. Although we expected the work to take a long time, due to the quantity dirt, progress was complicated this week by an unexpectedly hard layer in the sediments above our target sand. The diatomite layer was particularly well cemented; usually it will break readily. In fact, it bent one of our picks.
The Locality B excavation is nearing completion already, as the Member 8 layer has nearly been completely removed, and all of the fossils have been carefully exposed. Preservatives applied to the fossils will keep them from disintegrating, and we will extract them on Monday or Tuesday. One of the reasons we needed to set up a datum in Locality B is to allow us to remove the bones from this site. In order to remove fossils, we need to be able to record their position on our grid. So far, a preliminary analysis of the bones is indicative of a single individual, a large grazing animal. A more detailed study will have to wait until we are out of the field and back in the museum lab.
At Site 15 (the Elephant Site) we have nearly reached the target paleosol. Excavation continues in 5 cm spits and the excavators continue to careful pick through the sediments for fossils or stone artifacts. The microfauna fossils which are being recovered from the sediments are aiding our research on environmental change in the Olorgesailie Basin 990,000 years ago. Careful study of microfauna above the elephant layer coupled with our data on the environment during the time of the elephant layer will give us insight into any environmental change that took place and the rate at which it took place.