Digging the DHA

15 July, 2017

Knysna, South Africa

Our first week had flown by, and the second arrived just as quickly. With the setup complete, we were moving a LOT of sediment and artifacts. We had six excavators, two gunners, and one recorder, all under the direction of our PI, Dr C. 

First, a brief background: our site uses the UTM (Universal Transverse Mercator), meaning that it’s part of a mapped grid zone. This allows us to set up squares within this grid, which are given numbers based on the southing and easting. Within each square are four quads, labeled SW, NW and so forth. When we dig, we open lots, a numerical sequence to track any change; and stratunits, a similar alphabetical sequence. However, while stratunits begin over again each season (only the year changes, for example, K16A, K17A, K17AA, and so forth), lots never repeat. Lots and their associated strats are opened with a photograph, a sediment sample is taken, and they remain open while the color, texture, and artifact densities remain the same. Once they change, the lot is closed, notes are taken, and a new lot can be opened.

My quad was in the eastern section, in a stratigraphic layer we refer to as the Dense Hearth Aggregate (DHA), because it’s a patchwork of hearths. Artifact density is high, and the sediment can vary from black to white, depending on the layers of ash. These appear to be made during the Middle Stone Age to the Later Stone Age transition, or when people stopped using stone tools about finger length and started making them fingernail size instead.

I was sandwiched between another hearth excavator, and two MAP crew members who were rapidly removing a layer of shell. This thick layer is predecessor to the shell midden, a Holocene deposit stacked high above our hearths (who knew there could be that much shell? That it would fragment into shell dust?). We do like the Dense Shelly layer, and hope it will explain more about the technology and subsistence patterns of the inhabitants.

My quad was really less than a quarter of a quad. I was tasked with removing a white ash layer (hearth) from its resting place. There were numerous small artifacts lying around, including two nice pieces of bone.

I got to work. Excavation is harder than it looks, especially when the sediment is concreted, and you’ve been warned not to break the fauna. Needless to say, it went slowly. More slowly because I can’t just uncover something and then remove it (that would be too easy, and would decidedly lack the mountain of paperwork necessary for a proper excavation). Instead of drawing everything in the old fashioned way, we use a delightedly high tech devise called a Total Station, or gun. Its really a piece of survey equipment that archaeologists discovered and put to work, helping us to “instantly” capture spatial data.

Our gunner was an ASU graduate student. Luckily, she’s had experience at other sites, and wasn’t fazed by the intense number of shots. Less lucky was my trenchmate, who was always blocking the laser. He often ended up sitting on the gun platform, scanning barcodes for my finds.

One of our gunners

After two days of continuous but slow progress, the hearth was removed. Instead of working on the sediment below the hearth, we all moved from the lower squares to the higher north ones.

Now I was in a less constrained but equally dense layer. This one covered the whole quad, and during previous seasons had seen the removal of several hearths. Now, there was only dull brown dirt and a ridiculous number of tiny bits of charcoal, half of which were nearly impossible to see until after you’d scrapped through them. The further I dug, the more fauna I found, which was great news for someone as obsessed with bones as I am. This may have slowed my digging, as I took the time to clean and examine the fauna (perhaps this is why I am spending half the season in lab).

At various times throughout the day, we caught glimpses of a pod of dolphins traveling up and down the coastline. Whoever was lucky enough (or bored enough) to be scanning the horizon would alert the rest of the crew. We had regular wildlife watching breaks at the sight of dozens of fins flitting through the water. Afterward, I asked the remaining crew members if they had seen the 50 dolphins. The words I should have used were “approximately 50 dolphins,” because everyone is still waiting to hear how I got such a precise number of fast moving marine mammals.

As Friday rolled around, I still hadn’t removed the entire layer, and my gunner was leaving. A black hearth was beginning to spring forth from the area, and I was getting tired of trying to capture bits of charcoal.

Although we had decided against a braai that evening, our crew was game to visit a local pub, which was rumored to have great chips (i.e. French fries), and beer. We packed up a bit early, hiked out, loaded the vehicles, and dropped people off at the pub, before heading to the flats to unload the equipment and pick up the rest of the crew. By the time we left, several people were getting ready to head to dinner, i.e. the wifi, so a small group headed back out.

Unfortunately for us, it was oysterfest, involving a carnival, a plethora of footraces, and other exciting events. As I had spent some time previously driving around the town, I was well acquainted with the insane traffic that struggled to fit into Knysna. During osterfest, it was bumper to bumper on the narrow roads. This Friday evening, the eastbound lanes were beyond full, stretching from one end of town to the other.

We settled in for a long ride. After a day of hard work, fresh air, and hiking, we were starving. Slowly we crept around the lagoon. Nearly an eternity later, we arrived to find that chips (French fries) were coming soon. Our comrades had commandeered a table on the wooden deck, under towering trees. The sky was fading, the bright sunset hues mixing and darkening to black. The now chilly air didn’t bother us, distracted as we were by plates of chips and tall glasses.

Too soon, we were piling into the car, heading for warm showers and the weekend.

Saturday, most of our crew headed out to the western Head to survey several caves. We hiked along sandy beaches, scrambled over boulders, climbed slabs of cemented dune, and clung to the sides of cliffs. Best job in the world. 

 What Ledge?

Exploring the cave