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    Wednesday 21st March 2018: Lisa Grey, Archaeobiology

    Note: Illustrations have not been included with the following report

    Lisa’s talk, which had to be re-scheduled from 28th February due to inclement weather, proved to be a fascinating and slightly unusual event for us, as Lisa brought in a selection of biological materials she has worked with, together with a microscope (one of the main tools of her trade).  

    She ran through her succession of posts over the last twenty years, from the time she was an Archaeobotanist with the Museum of London Archaeological Service and was involved in analysing materials found during many excavations in the capital, through her studies at UCL where she gained an MA in Maritime Archaeology and an MSc in Bioarchaeology (Archaeobotany Option), to her time at The University of Wales where she gained a BA Hons in Archaeology and Environmental Studies. From 2002 she has been based in Faversham, and has been a Self Employed Sole Trader, working on post-excavation assessments and analyses of macroscopic plant remains from archaeological sites in a number of countries, together with processing samples and giving sampling advice. Outreach is an important part of her work, and she has run workshops and given talks to adults and children on aspects of environmental archaeology.

    Lisa passed round a number of specimens of biological and plant materials kept in glass sample containers, and demonstrated the use of the microscope to those wishing to examine the materials more closely. Lisa said that she does not get involved in pollen analysis, as this is a rather specialised field, or usually studies coprolites (semi fossilised animal dung, which contains biological materials such as plant fibres and seeds which tell us what foodstuffs were being consumed in ancient times). She explained that ancient seeds such as grain could be studied as they were often charred, carbonised, or subject to silification or mineralisation. She pointed out that plant matter was often preserved in waterlogged situations where lack of oxygen prevented or minimised decay.

    Lisa explained how the various technical methods used to recover biological samples worked, such as dry and wet sieving, and the use of flotation tanks such as the Siraf equipment. A flotation machine is commonly used to separate materials mixed up together in bulk soil samples. The sample is added to the flotation equipment and the overflowing water (with charred finds) is caught by pouring the mixture through a pair of larger to smaller sieves. Within the flotation tank a metal screen holds the weight of the sample and separates it from the incoming water spout. Beneath the sample another mesh is usually placed, which acts as a wet sieve to retain bone, artefacts, and stones. Fine sands, silts and clays settle out as sludge at the bottom of the flotation tank beneath the water spout, and needs to be cleaned out periodically.

    While working in London Lisa described two interesting finds she came across, the first being when a large Roman cemetery was being excavated in the Spitalfields area and a beautiful lead coffin, decorated with scallop shells, was found. Within the coffin were the remains of a woman accompanied by grave goods, which including fragile glass artefacts and ornaments made of jet. Of particular interest to Lisa was that in a layer of silt beneath the skeleton were the remains of the bay leaves on which her head had been cushioned.

    A more surprising find was the remains of a blackened banana skin found in a mid-Tudor rubbish tip, which is the oldest direct evidence for banana being found in the UK, and which pre-dates previous evidence by some 200 years. Speculation is that bananas were relatively common in Tudor England, in which case they must have been consumed when they were over-ripe as it took weeks for them to be shipped in from Africa. There is no literary evidence to back this up as it is not known what name bananas were given in Tudor times.

     

    As she is an experienced and enthusiastic diver Lisa is particularly interested in maritime archaeobotany (the study of shipwreck finds and submerged and intertidal landscapes), and one of the samples she brought in was of exotic seeds found during the underwater examination of a rare shipwreck found off the coast of Oman. The ship was almost certainly the late C15th ship the Esmeralda, one of Vasco de Gama’s fleet which was wrecked during the first ever attempt to navigate directly from Europe to India. An interesting website to visit can be found at esmeraldashipwreck.com, where detailed information concerning the project can be found.

    As Lisa was addressing an Egyptological group she mentioned work that has been done to investigate brewing methods used in Ancient Egypt.  Bread was a staple of the Egyptian diet, and beer was a by-product of its making. Bakeries were not only used to produce bread but also to brew beer, as beer was produced using fermented wheat or stale bread. The common beer was not like today’s brews, as it was much thicker and with an almost soup-like consistency. It appears that beer was made by crumbling bread into water and letting it be fermented by yeast from the bread, yielding a coarse liquid swimming with chaff.  Beer residues and desiccated bread loaves from Egyptian tombs have been studied, and a microscopic analysis of beer residues in the walls of pots indicates a more elaborate brewing process developed in later times, which involved the blending of cooked and uncooked malt with water, which produced a refined liquid relatively free of husk.

    Roger Sharp