Today
we started with a quick tour around some of the new sites that we surveyed
yesterday. We needed to get to the antelope horn core site, in Member 9 just
to the south of camp, to put "Butvar" on the fossil. Butvar Plus
B98 is a preservative that forms a clear, strong layer over the surface
of the fossil, preventing cracking and fragmentation. Another important aspect
of Butvar is that with a little thinning agent, it is possible to completely
remove it in the lab -- allowing us to restore the fossil to its original
shape, and to study its original surface for things such as cut marks. For
something as rare in the Olorgesailie Formation as a horn core, we wanted
to get the Butvar on it as soon as possible, because when fossils are exposed,
they can be weathered and destroyed very quickly. We hope that this site will
contain more fossils within the outcrop, but we will have to wait and see.
After
we visited this site we walked to another site in the same member that showed
many fossils coming out of the outcrop. We decided to take the circuitous
route; longer, more difficult terrain, but more chance at seeing things on
the way. As is often the case here at Olorgesailie, we came across an area
where a large number of stone tools and fossils were eroding out of a sandy
portion of Member 9. We found a hippopotamus tooth, fish fossils, and a several
stone tools in the erosional surface, including an Acheulean handaxe. The
handaxe was about 20 cm in length and was quite impressive.
Later on, we performed a second lift at Site B8-1 (which we are now going to have to rename "Site B7/8-1" because of the fossil finds in the Member 7 part of the site). During the lift we documented over forty new artifacts and fossils, and we were able to get all of the stone tools out. The bones, however, will have to wait until Monday or Tuesday. It is an extremely complicated site, with many of the bones overlapping, and all of the bones extremely fragile. Several of the bones have started to break into a fine dust when we attempt to clear the sediments away from the surface. We have sealed the surfaces with preservatives, so that we can restore them in the lab. We will need to proceed cautiously. After the lift was finished, we excavated the pedestals that the fossils and stones were on, and found three new stone tools.
In
addition, we collected nodules of calcium carbonate from the paleosol layer,
in the levels associated with the fossils and tools. These nodules will be
sent to the Smithsonian for stable isotope analysis, which will tell us what
the original vegetation was like when the soil was formed. If it is true that
the large fossil animal we have found is a browsing rhinoceros, we would expect
that the environment was comprised of thickets, bushes and trees, rather than
grasses. This isotope study should help us test this idea.
-RP