Life on the Edge

July 1, 2019

This is our sixth field season at Knysna, South Africa, (my fifth) and as usual, it’s great to be back on the South African coast. One of the entertaining things about this blog is documenting the changes which occur over the years. This field season we have greatly expanded the scope of our excavations, by bringing in a larger crew and opening excavations both above and below our previous work. Additionally, we have made some improvements to the site, especially where safety is concerned. One of the best ones is the inclusion of a chain along one of the sketchier parts of the climb. Not only has this improved the general safety of the crew, but it also means that whoever is passing heavy, equipment-laden packs along the ledge is now actually secured to the ledge.

The chain and the ledge

MAP crew excavating

There are now nine HOMER (Human Origins Migrations EvolutionResearch) students onsite, as well as the local MAPCRM crew. The students are from universities across the USA, and will be trained here before heading to the HOMER site in Malawi. The MAPCRM crew have excavated for a decade at the nearby site of Pinnacle Point, and are some of the best in the business.

HOMER student editing the geodatabase

HOMER student "gunning" (operating a Total station)

Previous and current excavations at the site have focused on targeting the Middle and Later Stone age transitions, a period which is absent at many coastal archaeological sites. It’s a period of interesting technological change amid climatic upheaval, thus, archaeologists find it fascinating (at least, some of us do). The main exaction trench has already yielded tens of thousands of artifacts, and we are hard at work expanding it this season. One of our goals is to understand how deep the deposits are, i.e. how long have people been using the site? In order to do this, last season we took our trench and cut it down until we hit bedrock. This year, we have moved the trench outside the cave and to the east, where we hope human activity was more likely to occur and may have been better preserved.

Our main excavations

This was a multi-step process, beginning with finding the grid line that extended out of the cave. The easiest and most accurate way to do this is to use one of the total stations and map the location based on geodatabase. Conveniently, there is a tall steep rock in front of the cave, which is high enough to avoid most wave action and see the area we were intending to dig. It’s also far enough away that we had to communicate with hand signals and some amount of yelling. This led to more or less accurate placement of a line down the steep slope, revealing the easternmost edge of our upcoming excavations.

Mapping the slope

However, before we could dig, a large amount of vegetation needed to be removed. Which meant someone (in this case, me), was required to rope in and scramble up and down the side of the cliff. The section is steep, with loose topsoil, displaced artifacts, and stubby fynbos. It’s steeper than it looks, and has been the downfall of several water bottles over the years. Cutting back the vegetation revealed an unfortunate amount of rocks and spiders, the latter of which at least had the decency to run away. Rocks had to be hurled down the slope into the ocean.

Before excavation or vegetation removal

Once the vegetations had been cleared, we were ready to dig. In actuality, most of the exposed sediment is either topsoil, slip from deposits, sand (this is an anthropogenic, modern deposit from the archaeologists), or rockfall. Tangled roots bound rock and dirt together, slowing progress. Eventually, we cut it back to expose a dense rock layer. Beyond these rocks, we hope, are archaeological deposits. Afterward, we needed to cover the newly exposed surface with a protective layer of sandbags and cut another step into the hillside above the excavation. In this manner, we worked our way up the slope to the cave mouth.

Two steps up

Excavations continue

Removing so much of the hillside requires a stabilizing force to be inserted. In our case, this means hauling many (dozens) of sandbags up the cliff to site. Sandbags are the building blocks of our site (and many other coastal archaeological sites): bracing walls, providing stable platforms for the total stations, and at KEH-1, a staircase along and up the cliff. For every step we cut into the slope, we moved more sandbags, and constructed another platform. 

Sandbag bucket chain

Despite our platform building prowess, there are plenty of precarious positions to be had on the side of the cliff. Every time a total station is set up to map the lower area, we gauge which location has the least probability of death, and set the tripod there. The humans won’t fall far, as we’re all required to be harnessed to a rope. Photographing the section can sometimes be even trickier, although possible with caution and more rope. 

camera angles

Placement 1

 At the end of two weeks, we have almost reached the top of the sediment, placing our new excavations even with the mouth of the cave. Hopefully, the next week will reveal the continuous sequence we are searching for.

End of day, Friday June 28th