Sorting residues for palaeobotanical material
Sorting residues for palaeobotanical material

Palaeobotany at Portus

Palaeobotanical remains are used in many different ways at Portus. For example, charcoal has the potential to tell us about the use of fuel and the trees grown in the vicinity. Local conditions result in the survival of a great variety of organics and so we collect soil samples so it can be looked at closely. In fact we use a variety of methods to explore the organic remains, and it is extraordinary what we can learn from the smallest of finds.

Washing palaeobotanical material from soil samples

Washing palaeobotanical material from soil samples - Hembo Pagi © University of Southampton

For example, in the early stages of the Portus Project work by Rachel Ballantyne and Evi Margaritis focused on two specific aims: evaluating the quality and diversity of preserved biological material at Portus, and helping to understand the ways in which contexts were formed.They describe their work as follows:

“A major task for the first excavation season was to instigate a processing system for flotation of selected contexts; acquiring all the necessary equipment, and then organising the paperwork and labour for processing itself. This task was successfully completed, and the team managed to collect and process 22 bulk samples from 18 contexts. Loose sandy and silty sediments predominate at Portus, and so shallower levels of the stratigraphy exhibited high amounts of bioturbation with frequent roots, other partially decayed modern plant matter, and arthropods.

“The flotation sieving produced two components from each sample – a ‘flot’ comprising all low-density items (charred plants, modern roots, pumice etc.) and a ‘heavy residue’ of high-density items (most artefacts, bone and bivalve molluscs).” (Ballantyne and Margaritis 2008: Portus environmental analysis talk)

Drying palaeobotanical finds

Drying palaeobotanical finds - Hembo Pagi © University of Southampton

The former study demonstrated considerable diversity. For example, the majority of the plant remains could be identified as being “of economic taxa” i.e. staples such as wheat, barley, lentils, stone pine seeds and vegetables. The burning indicates that this was generally a consequence of their cooking (whether planned or accidental!). In terms of the relationship of these to contexts it was possible for them to identify clear deposits with intensive human cooking activity (potentially dumps of cooking waste) and other areas with no sign of human interaction.

In terms of the latter aim a good example stems from comparison of sand deposits at different locations around the Imperial Palace. These deposits were sampled using an auger (a power or hand drill for extracting soil samples from deep underground – we will learn more about this in Week Three). Some of these samples were deliberately taken to coincide with areas of intensive geophysical survey, using multiple methods including electrical resistance tomography which provides a sense of different levels of buried material underground. Again, you will learn more about these methods next week.

Some differences were noticed in the type of sand recovered in these different augur locations. These differences in turn suggested that it was deposited through different processes. The palaeobotanical (alongside the zooarchaeological) evidence demonstrated differentiation between marine and land species in some zones, and in others a mixture of the two suggesting a deliberate dumping of material to fill in an earlier dock or canal, with the sand possibly derived from shore deposits or dredged material. However, our colleague Ferreol’s palaeo-environmental coring (that we learn about next week) tells us that these sandy levels were natural deposits belonging to beach that predated the construction of the Trajanic infrastructure and buildings here.

Specifically the two techniques were used to identify and quantify charred plant remains, small bone (incl. fish/birds), edible molluscs such as a profusion of cockles and also organic remains, ecofactual molluscs and microfossils including seeds and insects. This provides a fascinating level of detail. For example, the organic plant remains could make it clear whether deeply buried parts of the site had always been wet or whether there had been an early period prior to them becoming waterlogged.

By microscopic examination of what can honestly (and unfairly!) seem like a tray of dirt our experts can talk about the seeds of goosefoots (Chenopodium sp), stitchworts (Stellaria sp.) and plants from the Nightshade Family (Solanaceae) and in turn describe the environment at that time (Rachel Ballantyne 2007: report on the environmental evidence from the auger samples).

It is another magical scientific process, and it is only through the meticulous combination of these materials and methods that such conclusions can be drawn and evaluated.

Smelling the past?

Since the first run of the course I spoke to Rachel again, this time about the smell of Portus. The olfactory sense is not often discussed in archaeological literature and yet it plays a very significant role in human experience. A single smell can easily conjure a memory from long ago. So, I asked Rachel what we could put in our shopping baskets if we want to recreate the smells of the port:

“The usual harbour-side stench of decaying marine detritus is probably the first one that comes to mind..! How about you buy some dried edible seaweed (any sort) and leave it in water in the sun for a few days? Not nice at all! Wheat-filled granary stores, overlaid with the subtle scent of black peppercorns are two others where we actually have good evidence. The smell from bags of wheat grain - the unmilled type that is popular these days for sprouting - and bags of peppercorns would certainly conjure the same smell.

I also think that that there would have been a major contrast between the exterior, harbour-side smells and interior, clean, dry spaces of the Magazzini, which is where the smells of the traded materials may have taken pre-eminence. Other facets are wood smoke in some open areas of the site where there was quite a lot of charcoal recovered, and the smell of decaying refuse tips in other areas. The dumps of ceramic we find on the site are perhaps a good indicator of where refuse tips might have been. And of course refuse tips attract scavenging fauna such as dogs and rodents, which also tend to smell, so the dog owners amongst the learners might be able to experience that!”

If any of you do assemble the “smells of Portus” we would be very interested to see whether you think it helps you to imagine the place. Dragana will talk more about the use of imagination in archaeological theory later in the course, but you might want to search for the term “phenomenology” online for an insight into one approach pursued by archaeologists, using contemporary sensory experiences to inform ideas about the past.

Graeme


Point to consider:

When some of us from the Portus Project worked at the site of Myos Hormos in Egypt we found many peppercorns that had been imported from the East. What other things could plant remains tell us?


[Extra] References and sources:

  • Brothwell, D. and Pollard, A.M. (eds). Handbook of archaeological sciences
  • Balick, M. J. and Cox, P. A. (1996). Plants, People, and Culture. New York: Scientific American Library.
  • Hastorf, C. A. and Popper, V. S. (1989). Current Paleoethnobotany: Analytical Methods and Cultural Interpretations of Archaeological Plant Remains . Chicago: University of Chicago Press.
  • Pearsall, D. M. (2000). Paleoethnobotany: A Handbook of Procedures. San Diego: Academic Press.

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Archaeology of Portus: Exploring the Lost Harbour of Ancient Rome

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