Saturday was a really memorable day. We finally got to see the Isimila Acheulean site. I’d been reading about it for decades so I was very excited and James, who told me he had been literally dreaming about the place for years, was like a kid on Christmas Eve.
It’s the rainy season at the moment and Tanzania is very green, particularly in the highlands. The mountains and kopjes are blanketed in forest and dense thorn bush. Around Iringa, where we were staying, there are wide valleys, some with substantial rivers, and broad plains separated by long chains of rounded hills. Isimila sits in such a valley with low hills to the north, east and south. Imagine a snooker table with a jagged tear in the base filled with white chalk. That’s what the Isimila donga looks like from a nearby vantage point.
I knew about the richness of the site from others who had visited, and my work in South Africa had prepared me for a carpet of artefacts, but I was still blown away by the sheer quantity of archaeology. Everywhere you turn there are handaxes and cleavers in beautiful condition. Some parts of the site are literally an artefact gravel, with LCTs more common than the natural background rubble.
Clark Howell and his colleagues interpreted the sedimentary sequence as a gradually contracting small lake or pond (some pond!), although later investigators saw a stronger fluvial input. Some of the artefacts are definitely associated with small to medium sized gravels, but others clearly lie in fine grained sediments which are predominantly silts and fine sands with a varying clay content.
The first things that strike you about the LCTs are the size and freshness of the artefacts, something the original excavators were keen to point out. For a technologist like myself the handaxes and cleavers are mouth-watering – an odd expression to choose perhaps, but those of you who appreciate a well-turned Acheulean flake-blank will know exactly what I mean. The Isimila donga is famous for the giant handaxes recovered by Maclennan. Although we didn’t find any giants, there are some really big handaxes and cleavers present. It’s not hard to imagine the giants were the extreme end of a spectrum that naturally included big handaxes and cleavers.
We spent the whole day there, wandering the donga and trying to recreate the stratigraphy of Clark Howell and his team. We also visited the spectacular columnar erosion features in the South Gorge, a well-known geological locality. Here induration of the sediments below caps of what looks like ferricrete has left pillars while running water has removed the surrounding substrate. Picture a forest of yellow pencils with red rubbers on the end, a powerful reminder of just how dramatic erosion can be in these environments – as is the donga itself.
At the end of the day Pastory, Habib, James and I, sat outside the little museum above the donga enjoying a beer, completely overwhelmed by the experience of the day, exhausted but happy. The Isimila Museum, run by Mr Ngoma and his staff is a great introduction to the site and the local history of the region.
So it was back to Dar and another memorable drive through the Mikumi National Park. This time a small herd of elephant was feeding close to the roadway, and a family of curious giraffe watched someone changing the wheel on their car – ‘you don’t want to do it like that mate…’
Tomorrow Pastory James and I head for the National Museum to meet colleagues and begin looking at the collections from Isimila. The artefact lover in me can’t wait.
Wishing you were all here,