Tag Archives: Corinthia

Sampling and collection strategies in Mediterranean survey

I’ve just finished reading Andy Bevan’s and James Conolly’s book on their archaeological survey of Antikythera, Mediterranean Islands, Fragile Communities and Persistent Landscapes: Antikythera in Long-Term Perspective (Cambridge University Press 2013). It is a very impressive book about a very impressive archaeological project. In two seasons, they surveyed virtually the entire island (18.58 sq km, 90% of the island’s total area) with walkers spaced fairly tightly (15 m). They collected their tract data every 10 m, so every sherd collected in fieldwalking can be located within a 20 sq m strip. There is some error involved in this, but nevertheless this is, as far as I know, the best spatial control that has been achieved by any field survey in the Mediterranean.

I’m going to skip discussion of the analyses (which equally impress) because I was particularly interested in their collection strategies (for regular tractwalking, as opposed to more intensive “site” collection strategies).  Fieldwalkers counted all artifacts they saw in a corridor extending 1-2 meters on either side of their line and collected feature sherds: i.e., “rims, bases and handles, decorated body sherds” (14). Now obviously such a strategy is a compromise, as all collection strategies are. Bevan and Conolly write that “we see the collection of feature sherds as a reasonably sensible fieldwork compromise” (53) and I don’t disagree. Where I do disagree is when they go on to say (in the next sentence, same page) that

Many of the proposed alternatives, such as only collecting a ‘representative’ example of each type of sherd found in the current survey unit (Moore 2008), are substantially less effective because they tend to force very high-level interpretative decisions (e.g., about what exact kinds of pottery styles and fabrics are present) to be made very early on in the field, prior to artefact cleaning and without much overview of the entire assemblage (which also leads to significant practical delays if only one or two specialists are asked to make this decision or much greater bias if a wider group of semi-trained surveyors are asked to do so).

Moore 2008 is an article by Scott Moore, a ceramicist with whom I’ve worked in Cyprus (PKAP); the article describes the Chronotype system developed by Timothy Gregory, with whom I’ve worked in the eastern Corinthia (EKAS), so I’m pretty familiar with the system. I’ve worked with it for six or seven field seasons at those projects. And I don’t think that the critique of it by Bevan and Conolly is fair.

The criticism, to recap, is that this system (and others like it) require high-level interpretive decisions in the field, prior to cleaning and without much overview of the entire assemblage. What is this high-level interpretive decision? Field walkers are instructed to pick up the first artifact they see and every other artifact that is different (with respect to fabric, surface treatment, body part, and thickness), and that if they are uncertain whether an artifact is different, to collect it.

Now this doesn’t seem to me to require much high-level interpretation. My experience is that it’s pretty straightforward. The walkers don’t need to know “what exact kinds of pottery styles and fabrics are present” nor do they need to have an “overview of the entire assemblage” (Bevan and Conolly 2013, 53). They just pick up what they see, and if it might be different, they collect it. The experience of everyone who has used the Chronotype system (and this is also based on experimental data) is that field walkers overcollect, i.e., collect redundant data, so that if the field walkers make any mistakes, it is in the direction of total collection. (This is a summary of Gregory 2004: 28-29, published here and cited elsewhere by Bevan and Conolly).

The other issue is that the identification of what is and what is not a feature sherd is a kind of decision (high-level or otherwise), so that the “feature sherd” collection strategy is open to the same criticism: i.e., that it forces field walkers to make a decision before the artifact has been cleaned. I suppose that a critic would point out that it’s easy to identify handles and rims and bases, and I suppose that it is. But it’s not clear to me — maybe it’s clear to everyone else — that it’s so much easier than what Chronotype asks you to do. The other issue is what happens when a fieldwalker is uncertain? In the Chronotype system, the impulse drilled into fieldwalkers is “when in doubt, collect.” What if, using the “feature sherd” strategy, a sherd looks like a plain body sherd, but in actuality preserves a tiny portion of the rim that goes unnoticed? Perhaps the fieldwalker would collect it anyway. But I would guess that in most cases, s/he would not.

In any case, this brings us to the weakness of “feature sherd” collection strategies: they do not collect sherds that are potentially diagnostic. As Bevan and Conolly repeatedly point out, fabrics are important indicators of chronology, function, and even origin, and they are becoming more and more important over time, not less. I point this out because as Bevan and Conolly (52) correctly observe, the

significant discrepancy between what we now know and what we might know in <the> future, is one of the reasons we feel strongly that surface survey, like other kinds of archaeological fieldwork, should make systematic, permanent artefact collections …*

All this is not to say that the Chronotype system is perfect: it is certainly not. In fact, if I were doing survey in Antikythera, I would not use it. So I am certainly not questioning their decision to collect feature sherds. After all, the proof of the pudding is in the eating, and there is no doubt that Bevan and Conolly have provided us with rich and nourishing results (to extend the metaphor rather awkwardly). But neither do I think that the critique of Bevan and Conolly is fair, nor do I think that we can solve all of our problems by collecting feature sherds only.

The problem here is rather more complex, I think, and it has to do with research design, a theme that featured prominently in an article that I co-authored with Bill Caraher and David Pettegrew in 2006. Selective collection (i.e., collecting feature sherds, and especially the Chronotype collection method) is a way to reduce the collection of redundant data. On the Eastern Korinthia Archaeological Survey (EKAS), for instance, the project counted 146,599 artifacts in only 3.85 sq km. The Antikythera survey, in contrast, counted 66,000 artifacts in 18.58 sq km. That is a huge difference! It is somewhat larger than it seems, of course, because EKAS used a tighter 10 m walker spacing as opposed to Antikythera’s 15 m, but if we correct for that, we will see that EKAS counted over 7 times as much pottery as Antikythera did. What about collection? EKAS collected 38,337 artifacts (26%), Antikythera collected 25,675 (39%) by my count of their open data, which I downloaded here.

It’s probably impossible to find a place to do survey in Greece that is more different than the Corinthia than Antikythera (or the other way around, depending on your perspective!), and so the differences in the collection strategies aren’t that surprising. The Corinthia is a high-density artifactual landscape, even for Greece. Antikythera is very low-density, in part because (a) there are virtually no rooftiles (my dream!!!) and (b) for significant periods of its history, the island was abandoned or had a very low population. So a survey in Corinthia needs to find ways to cope with the fact that a high-intensity collection strategy would have produced insane numbers of artifacts. This is simply not a concern of a survey in a place like Antikythera (or at least, it’s a pretty minor concern). All of us, I think, would agree that it makes no sense to sample a high-density artifactual landscape the same way you would sample a low-density artifactual landscape. The lower the density, the more sense it makes to move towards total collection and towards piece-plotting individual finds.

In sum, I’d argue that the Chronotype collection strategy, flawed as it may be, is one way to deal with a particular problem. I’d readily concede that it may not be the best. On the other hand, it does do a good job at (a) reducing the collection of redundant data, (b) collecting useful qualitative and (to a lesser extent) quantitative data about the surface assemblage, and (c) avoiding the potential biasing effect of ignoring non-decorated body sherds that can, despite their humble appearances, be highly diagnostic (my ceramicist friends insist that they can do a lot with body sherds, and I believe them).

This is not to say that Bevan and Conolly did the wrong thing: I don’t think that at all. But I do think that we need to weigh the advantages and disadvantages of our methods with clarity. This is something that is a real strength of the Antikythera survey book, in fact. Their second chapter ends with a page of meditations on “methodological limitations.” So it is a minor criticism to pick them up on their brief discussion of collection strategies. My point is not to nitpick, but to extend the discussion about survey collection a bit further, beyond the text of their immensely rewarding book.

Notes
* In the … I have omitted reference to the same article by Timothy Gregory (2004), which advocates for processing artifacts in the field, although it should be pointed out, as Gregory indeed does (2004:30), that this procedure was instituted by necessity, due to restrictions placed on the survey in the archaeological permit.

Blegen’s notebooks from Korakou

This is the first post of a blog dedicated to my research interests, which center on the archaeology and scripts of the Aegean Bronze Age. The name of the site, Englianos, is the modern toponym where Carl Blegen excavated the “Palace of Nestor.” This site, which was called Pylos in the Late Bronze Age, is the source for some 1000 inscribed clay documents whose study formed the basis for my doctoral dissertation.

Prior to excavating LBA Pylos, Blegen excavated at a number of other prehistoric sites in the Peloponnese, one of which is Korakou. This site, located on the bluffs overlooking the Corinthian Gulf at the outskirts of modern Corinth, was excavated in 1915 and 1916, and formed the basis for Blegen and Wace’s ceramic chronology of the Greek mainland for the Greek Bronze Age.

Blegen’s excavation notebooks have been scanned and made publicly available by the American School of Classical Studies at Athens and the Corinth Excavations (among other things). As my colleague Bill Caraher pointed out in his blog (about two years ago!), these are a fantastic resource, but they are static. There is no opportunity for scholars to add metadata to the digital scans. As Bill put it,

as I thought about this I began to imagine a parallel site where scholars could upload their transcriptions of notebook pages. These would be keyed to the stable urls provided by the American School and presented in a wiki which would allow for and track revisions. I am sure that some notebooks are useful enough and commonly investigated enough to warrant this.

I think that Bill is right, and I wanted to provide here a small example of the kind of thing that he envisioned, using Blegen’s Korakou notebooks as an example. As Bill noted, Blegen’s handwriting can be difficult to read. Transcriptions of all the Korakou notebooks were made in 2005 by myself and Sarah James, and could provide a valuable resource to scholars working on Korakou. We are not the only scholars who have made transcriptions of the Korakou notebooks, however. Others who have worked with the Korakou material have also transcribed sections for their own work, and in some cases there are discrepancies between their readings and ours. In Notebook 84, p. 81, Blegen writes (on my reading, based on autopsy):

I measure depth from semadi cut in stone on east wall of L above the trench. This mark is .20 below ground level so I add .20 in every case to measurements of depth.

This differs from the reading of Jerry Rutter (also based on autopsy, published in his 1974 dissertation, p. 108):

I measure depth from [?……?] cut in slope in east wall of L above the trench.  This mark is .20 below ground level so I add .20 in every case to measurements of depth.

Below is the image of the passage in question. I’ve increased the contrast so that the writing is more clear, but you can see the original scan here.

NB84_p81

This difference in readings is somewhat significant for how we understand the archaeology of Korakou and indeed Blegen’s methods in the field. Rutter goes on to argue, based on his reading of this passage, that (Rutter 1974: 108-109)

Not too much credence should be given to Blegen’s depth measurements…since the ground level to which these measurements refer no longer existed and had to be estimated at 0.20 above some obscure “cut”. It is quite possible that Blegen began his…sounding at ca 0.40-0.50 below ground level, the level of the earlier floor which he had uncovered on 19 June.  In this case, the uppermost wall in the sounding would have appeared not at 0.60 below ground level, but at 0.80-0.90, roughly the level of the bottom of the LH IIIB 1 fill on which House L was built.

If, on the other hand, we use my reading of Blegen’s notebook, then the measurements were taken from a mark (semadi is a transliteration of the Greek σημάδι) cut into a stone. This stone belongs to a wall of House L, and the tops of these walls are, as Blegen notes, 20-30 cm below ground level (Corinth NB 81, p. 220). Thus his measurements are reliable. And this potentially changes Rutter’s interpretation of this area, as Sarah James and I noted in an unpublished report that we submitted to Corinth Excavations in the summer of 2005:

Rutter suggests that Blegen’s enlargement of [Trench] L began at ca. 0.40 m below ground level, where he exposed an earlier floor. However, Blegen only exposed this floor “in the southern part of the Megaron,” and his enlargement of the pit in L is “to the east and south.”  It is likely that the southern part of the Megaron is roughly equal to the area south of the pit in L, which cuts diagonally across the northern half of the main room of House L (the Megaron).  However, the enlargement of the pit in L extended to the south and east, and to the east of pit L Blegen apparently had not dug down to 0.40.  Thus, L II probably represents an operation taking the enlargement down to 0.40, and then L III included both the eastern and southern parts of the enlargement.  As the eastern part of the enlargement is directly west of the eastern wall of House L, it makes good sense for Blegen to use the wall as a benchmark from which to measure depths.

In short, this means that Blegen does reveal a wall (with L III, NB 84, p. 127) whose top is only 0.60 m below ground level.  This is problematic for Rutter’s reconstruction of this area, specifically his argument that the “habitation level” revealed at a depth of 0.80 in the East Alley, and the “floor of hard earth” at a depth of 0.80 in Trench L (NB 81, p. 375), represent a terracing line for a fill of LH IIIB:1 date upon which House L was built.  Perhaps the “habitation level” at 0.80 is actually a floor associated with the construction of a building (represented by a wall whose socle rises 0.20 above its floor), which was then covered by the same LH IIIB:1 fill.

My primary interest here is not the interpretation of the area around House L at Korakou. Rather, it is that while static publications of excavation notebooks are invaluable, they do not (as they might) capture the scholarly arguments that build on these notebooks. What the American School has done — making a vast quantity of scholarly materials publicly available on the web — is laudable, but the next logical step is to turn these static materials into a dynamic scholarly space. A parallel wiki on the Corinth notebooks such as Bill and I are suggesting would allow scholars to add value to the static scans in a way that would benefit students and scholars of Greek archaeology for years to come.