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On Then Dig: Sanctifying Our Sites (Ceri Houlbrook) and open peer review…

November 20, 2013

Ceri Houlbrook’s contribution to Colleen Morgan’s Zeitgeist theme on Then Dig was posted this week. It’s called Sanctifying Our Sites:  Self-reflection on an archaeological dig, and discusses the archaeology of folklore and how investigating a site archaeologically can change the way it is perceived. The post was subject to open peer review, and Colleen very kindly invited me to be one of the reviewers, alongside Sara Gonzales from University of Washington, and you can read our comments at the end. It’s excellent reading. Take a look!

Call for Posts on Then Dig: Green

November 10, 2013

Then Dig is a collaborative archaeology blog hosted by UC Berkeley, and originally set up by Colleen Morgan and Alun Salt. I’m hosting the theme for November/ December, which is called “Green”, and is about how archaeology and palaeoecology can inform sustainability and conservation biology. Posts are welcome – please read the call below:

“Our theme for November is inspired by one of the earliest posts on this blog, DIY, Green Burials, and Mortuary Archaeology by Colleen Morgan. Archaeology and green issues are intrinsically linked, often explicitly in conservation legislature and in the designation of UNESCO World Heritage Sites, as well as in the public imagination (at times wrongly, as evidenced by an English politician’s characterisation last year of archaeologists as ‘bunny huggers’ – to see just how wrong this can be, read this extract of a recent paper on Hebridean archaeology by Mike Parker Pearson, Jacqui Mulville, Niall Sharples and Helen Smith).

As Martin Bell has noted:

 ‘Green concerns are about current and future trends. However understanding them requires knowledge of what has happened in the past’

(Bell 2004, p. 509). In this context, archaeological studies have been informative in issues such as the reintroduction of locally extinct animals, the development of sustainable farming and livestock management processes, the mitigation of agricultural soil erosion, and the prediction of potential outcomes of climate change.

Green concerns may also be more humanistic, and draw on archaeological imagery to suggest a utopian past where humans lived in sustainable coexistence with nature. Environmental archaeology has shown that such an idealised image of the past may not reflect reality, however – perhaps most dramatically in the famous case of Rapa Nui, which may have become unproductive after overzealous deforestation and poor land management (Bahn and Flenley 1992; Mann et al. 2008) (archaeological evidence does not necessarily support the idea of ‘ecocide’ however – Hunt 2007).

Additionally, indigenous knowledge traditions may be informative for environmental policy makers and planners (Johannes 1993, 33). Such knowledge can be drawn either directly from modern ethnographic studies (e.g. Costa-Neto 2000, 90, Blurton Jones and Konner 1989, 21), or inferred from archaeological and palaeoecological data (e.g. Jackson 2001; Mannino and Thomas 2002).

This theme welcomes posts which explore any interaction between archaeology and green concerns, including the topics discussed above, the environmental sustainability of archaeological practice, or personal reflections on how archaeology has made you think about green issues. If you’re interested in contributing a submission of 750 words or less, please e-mail me (LawMJ [at] with the title of your contribution as the subject line, or drop us a message on the facebook page or on twitter (@ThenDig). Posts will be published throughout November and December and are due by November 20th. Submissions in the form of images, music, video, and other multimedia are, as ever, also welcome. Your submission will be subjected to open peer review before being posted on Then Dig (our open peer review guidelines are here)


Bahn, P.G.,and J.R. Flenley, 1992. Easter Island, Earth Island. London: Thames and Hudson.

Bell, M., 2004. Archaeology and green issues. In J. Bintliff. Ed. A Companion to Archaeology Oxford: Blackwell. pp. 509-531.

Blurton Jones, N. and M.J. Konner, 1989. !Kung knowledge of animal behaviour. In R.E.Johannes Ed. Traditional Ecological Knowledge: A Collection of Essays Gland: IUCN. pp. 21-29.

Costa-Neto, E.M., 2000, Sustainable development and traditional knowledge: a case study in a Brazilian artisanal fisherman’s community. Sustainable Development 8, pp. 89-95. doi:10.1002/(SICI)1099-1719(200005)8:2<89::AID-SD130>3.0.CO;2-S.

Hunt, T.L., 2007. Rethinking Easter Island’s ecological catastrophe, Journal of Archaeological Science 34, pp. 485–502. doi:10.1016/j.jas.2006.10.003.

Jackson, J.B.C., et al., 2001. Historical overfishing and the recent collapse of coastal ecosystems. Science 293, pp. 629-638. doi: 10.1126/science.1059199.

Johannes, R.E., 1993. Integrating Traditional Ecological Knowledge and management with Environmental Impact Assessment. In J.T.Inglis, Ed. Traditional Ecological Knowledge: concepts and cases. pp. 33-39 .

Mann, D., et al., 2008. Drought, vegetation change, and human history on Rapa Nui (Isla de Pascua, Easter Island). Quaternary Research 69 (1), pp. 16–28. doi:10.1016/j.yqres.2007.10.009.

Mannino, M.A., and K.D.Thomas, 2002. Depletion of a resource? the impact of prehistoric human foraging on intertidal mollusc communities and its significance for human settlement, mobility and dispersal, World Archaeology 33 (3), pp. 452-474.”

An open bibliography for sustainability from archaeology and palaeoecology

October 17, 2013

I thought I would try using WikiArc to host crowd-sourced bibliographies, with the idea that they anybody can contribute to them, and that open access materials will be searchable using a Google custom search engine. I’ve started off with papers and books related to how archaeology and human palaeoecology can be used to inform sustainability and conservation biology, and you can read (and contribute to!) the bibliography here.

I’m unsure whether this idea has any mileage, but I’m eager to try. I’d like to have more open bibliographies on the site. Use the comments area below to suggest topics to cover.

An underground snail

September 21, 2013

A couple of weeks ago, I wrote about my modern mollusc survey at the archaeological site I have been working on, and mentioned that I had also seen Cecilioides acicula, a snail which lives underground, while excavating. I managed to take a picture of a live animal on my phone:

Live Cecilioides acicula

Cecilioides acicula – not a great photo, but you may just be able to see the white body of the snail protruding from the shell

As a subterranean species, C. acicula is problematic for archaeologists. It can occur in quite large numbers in samples, but is usually regarded as intrusive. I took a level of the spot I found this snail, and found it was living 90 cms under the former ground surface. In the seminal Land Snails in Archaeology (1972, 186), the late Professor John G. Evans reports that they have been seen 2 metres below the ground surface.

The shells are typically translucent, becoming opaque some time after the snail has died. Here are two very translucent (and quite pretty!) shells from a prehistoric sample elsewhere in Somerset – they are clearly a recent intrusion.

Translucent Cecilioides acicula shells

Translucent Cecilioides acicula shells

They are usually described as a medieval introduction to Britain from Europe (eg. Davies 2010, 170). I have only ever seen them in sediments with a good deal of sand or silt in the mix, and Evans (1972, 186) notes that they “are common in areas which have been cultivated recently but often absent from longstanding grassland which would appear to provide suitable habitats”. I’m interested to know more precisely when they arrived, and how they have come to be spread. In post-industrial Britain, it is not hard to envisage them being spread in soil with potted plants, but if they are truly a medieval introduction, was soil being moved around, or did they spread by some other means? Suggestions very welcome!


Davies, P., 2010. Land and freshwater molluscs. In T. O’Connor and N.Sykes, eds. Extinctions and Invasions: a social history of the British fauna. Oxford: Windgather Press. pp.175-180.

Evans, J.G., 1972. Land Snails in Archaeology. London: Seminar Press

Modern mollusc survey – hedgeline, Leighton, Somerset

August 25, 2013

Where I get the chance, which isn’t all that often, I like to take a look at the modern snail fauna of the sites I’m excavating. I’m currently working close to Leighton, between Shepton Mallet and Frome in Somerset. The site has a fairly sandy clay overlying Carboniferous limestone (the Hotwells Limestone) with occasional areas of younger, Jurassic, Inferior Oolite. It has been deeply ploughed, and maize was still growing there at the time of my survey. I couldn’t find a single snail amongst the maize, although the hedgeline (hazel, with some hawthorn) yielded quite a few snails.

The snail shells back home

The snail shells back home

The counts were

Cochlicopa lubrica 3
Discus rotundatus 1
Vallonia costata 1
Cepaea hortensis 4
Trochulus striolatus 21
Oxychilus cellarius 1

The C. hortensis were all of the 5-banded variety.
None of the snails were all that surprising for the environment – fairly typical hedgerow fauna.
Elsewhere on the site, in recent colluvium at the bottom of the hill, I’ve seen Cornu aspersum, in a very pointed form. Whilst excavating I’ve some across live examples of the subterranean Cecilioides acicula (which I only ever seem to see when the soil is quite sandy), and in the car park at the top of the hill there are Monacha cantiana.

Adventures in Ichnoarchaeology

July 3, 2013

Ichnology is the branch of palaeontology that deals with trace fossils – dinosaur footprints for example. Ichnoarchaeology, then, involves looking at similar traces of living things in archaeological contexts. The term was introduced in a stimulating call to arms by Baucon et al. (2008) (on – you can read it for free online but will need to sign in to download it). They review past work on archaeologically preserved footprints and handprints, on animal burrows, on invertebrate borings (such as woodworm), on trepanation of human skulls, and also suggest that coprolites (preserved faeces) and gnaw marks are also of ichnoarchaeological interest.

They state that the lack of a consistent ichnoarchaeological approach in all these cases means that “archaeologists are not taking full advantage of traces”. I’m not wholly convinced that this is the case.   I think that these different trace remains are rightly the preserve of different experts. Interpreting the preserved footprints of humans living beside the Severn Estuary 7000 years ago requires a very different expertise (more akin to biological anthropology) to interpreting the borings of a beetle in wood from the same site (more akin to entomology). Indeed, some specialisms have sprung up that are more specific than ichnoarchaeology – palaeodermatoglyphics (archaeologists and their long words…) for example, is the study of preserved fingerprints (such as those of a potter in the clay of ancient pots).

Coprolites, archaeologically speaking, are deposits and so positive contexts, unlike (e.g) animal burrows or footprints which are negative contexts because they do not add a new deposit to the stratigraphic record, so I think they are a different class of thing (in fact, Baucon et al. do say they are a grey area for ichnoarchaeology). As for trepanation, it requires a tool so is more like analysing toolmarks on worked wood than the direct evidence of a biological organism.

I probably won’t be using the term ichnoarchaeology very often (although I do recommend Baucon et al‘s paper), but I do think the concept provides quite a useful framework for looking at some classes of remains that aren’t often talked about when people talk about archaeology. Here then, are photographs some of my brushes with the ichnoarchaeological record.

Animal prints

Footprints (from humans and other animals) and handprints can be preserved in deposits which are very quickly sealed by another deposit. The classic example of this is in intertidal silts where the subsequent tide lays new sediment in the footprints. Such prints abound in the Severn Estuary, and have been well-studied on the Welsh side, forming the basis of a PhD by Rachel Scales and a number of papers by her and her colleagues at Reading John Allen and Martin Bell. Windblown sand can also preserve footprints, and hoofprints preserved this way have been excavated at Cladh Hallan on South Uist in the Western Isles. Where a sediment is artificially hardened, by firing for example, prints may be preserved, such as the pawprint in the first picture.

Dog pawprint on a wall at Bristol University

Dog pawprint on a wall at Bristol University

Excavated animal (probably cattle) hoofprints at a site on the Somerset levels

Excavated animal (probably cattle) hoofprints at a site on the Somerset Levels

Casts of hoofprints from the same site.

Casts of hoofprints from the same site.

A hoofprint before excavation

One of the hoofprints before excavation (below and slightly to the left of the trowel – not my finest photo).


Quite a few different invertebrates on land, in the sea and in freshwater bore into substances. Just yesterday I was talking to colleague in Poland about snails boring into rocks for calcium to build their shells (see this paper by Daniel Quettier for more details – with thanks to Aldona Kurzawska). Another burrowing mollusc, shipworm, can be a serious problem for wooden ships. Other molluscs and some insects prey on molluscs by making holes in their shells, while yet other invertebrates use mollusc shells as a substrate in which they live (Jessica Winder gives some great information about this with relation to oysters, for example here about sponge borings). On land, wood may be attacked by the larvae of a number of insects, perhaps most famously woodworm.

Beetle borings on waterlogged prehistoric wood

Beetle borings on waterlogged prehistoric wood

Calcareous tubes of Spirorbis sp. worms on a limpet shell from St Agnes, Isles of Scilly

Calcareous tubes of Spirorbis sp. worms on a limpet shell from St Agnes, Isles of Scilly

An oyster (Ostrea edulis) shell with tunnel from a polychaete worm (Polydora hoplura)

An oyster (Ostrea edulis) shell with tunnel from a polychaete worm (Polydora hoplura)

I have also written about the imprints of shells in clay here and in tufa here.


Rhizocretions are mineral tubes that form around plant roots due to ion exchange in carbonate rich sediments. They occur in some waterlogged estuarine and intertidal clays and look a bit like long streaks of rust.

Fragments of rhizocretions from prehistoric clays, Severn Estuary, UK

Fragments of rhizocretions from prehistoric clays, Severn Estuary, UK

Rhizocretions visible in the surface of an archaeological sediment before cleaning

Rhizocretions visible in the surface of an archaeological sediment before cleaning


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