CHAPTER 3: EXCAVATION
Note: this is part of an electronic companion that supplements Kevin Greene's book Archaeology: an introduction (1995); click on the title to start from the home page.

CHAPTER 3: EXCAVATION

COPYRIGHT STATEMENT
  1. THE DEVELOPMENT OF EXCAVATION TECHNIQUES
    1.1 The destruction of evidence, 1.2 The concept of stratification, 1.3 Pitt Rivers, 1.4 Developments in the twentieth century, 1.5 Mortimer Wheeler, 1.6 From keyholes to areas, 1.7 The interpretation of stratification
  2. AN EXAMPLE OF THE DEVELOPMENT OF EXCAVATION TECHNIQUES
  3. EXCAVATION PROCEDURE
    3.1 Selection of a site, 3.2 Planning an excavation, 3.3 Background research, 3.4 Staff and equipment, 3.5 Excavation strategy, 3.6 Recording, 3.7 Computerised processing of site records, 3.8 Publication
  4. EXCAVATION: SPECIAL CASES
    4.1 Camps and caves, 4.2 Waterlogged sites, 4.3 Underwater archaeology, 4.4 Graves
  5. THE EXCAVATION OF STRUCTURES
    5.1 The excavation of stone structures, 5.2 Timber structures, 5.3 Other building materials, 5.4 Reconstruction
Do you know a web site that would fit well into one of these sections? If so, please e-mail me!
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'Of all the archaeological activities described in this book, excavation has the highest profile in public perception, to the extent that anyone could be forgiven for gaining the incorrect impression that excavation is the primary activity of most archaeologists.' (p. 58)

1 THE DEVELOPMENT OF EXCAVATION TECHNIQUES

1.1 The destruction of evidence; 1.2 The concept of stratification; 1.3 Pitt Rivers; 1.4 Developments in the twentieth century; 1.5 Mortimer Wheeler; 1.6 From keyholes to areas; 1.7 The interpretation of stratification; Go back to chapter heading
'A few caves with prehistoric occupation ... were explored by removing the filling in layers to confirm that tools really were associated with bones of extinct animals. Most excavators sought to recover objects of commercial or aesthetic value by random digging on known sites, or by systematically plundering monuments such as burial mounds.' (p. 58)
1.1 The destruction of evidence
'What suffers from uncontrolled treasure hunting is the quality of information; coins, precious objects, or carvings have little meaning when divorced from their stratigraphic level or structural context.' (p. 61)
1.2 The concept of stratification
'A modern excavation peels away these layers in reverse order, and records the finds and structural evidence that they contain. However, the majority of nineteenth-century excavators observed stratification passively, rather than using it actively to guide their excavation strategy.' (p. 61)
1.3 Pitt Rivers
'Modern excavation practice does not have a single founder, but the kind of progress made in the late nineteenth century is exemplified by Pitt Rivers (1827-1900). ... The importance he attached to all finds, however trivial, led him to record not just the artefacts themselves but also the contexts in which they were found.' (p. 61-2)
1.4 Developments in the twentieth century
'Thus, three indispensable elements of excavation had emerged by the beginning of the twentieth century. Horizontal observations had improved considerably, and were combined with accurate recording, notably on German excavations of classical cities in Turkey. Vertical sequences were increasingly important, particularly on deeply stratified tell sites in the Near East such as Ashur... Systematic attention to all classes of finds was the newest and most important element...' (p. 63)
1.5 Mortimer Wheeler
'All three elements were combined in work conducted during the 1920s and 1930s by Mortimer Wheeler... Wheeler is chiefly remembered for perfecting the 'box system' of excavation, whereby a site was uncovered by means of a grid of square trenches, with baulks left standing between them as a permanent record of the stratification of all four sides of each trench.' (p. 64)
1.6 From keyholes to areas
'The interwar decades saw the development of open-area excavations on sites lying on flat alluvial land in southern Scandinavia, northern Germany and the Netherlands... Open-area excavations rarely use baulks at any stage. On sites of limited depth, this causes no problems, for the disturbed ploughsoil can be stripped off to reveal various features for individual study. This process can be extended to sites with deep stratigraphy if the extent, contours, depth and consistency of each layer are carefully recorded before it is removed.' (p. 64-7)
1.7 The interpretation of stratification
'All excavation is based on the fundamental principle of the succession of levels, which assumes that layers of soil (or any other material) were deposited in chronological order, with the oldest at the bottom. Today, even the simplest archaeological situation is still approached from the same point of view, whether it is a long sequence of layers recorded in section, or a direct relationship between two intersecting features in an area excavation.' (p. 67)

2 AN EXAMPLE OF THE DEVELOPMENT OF EXCAVATION TECHNIQUES: CORBRIDGE (NORTHUMBERLAND)

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'The large Roman site commonly referred to as Corstopitum lies just west of Corbridge, a small medieval town in the Tyne Valley, 24 miles (38 km) from the mouth of the river. It lay at the junction of two important Roman roads; Dere Street led from York into Scotland, while Stanegate continued west to the Solway, and marked the northern frontier of the Roman Empire for around thirty years before Hadrian's Wall was built 4 km to the north. The history of exploration at Corstopitum illustrates the changing aims and techniques of archaeology, from treasure hunting to investigation, from research to rescue, and from excavation to publication and display.' (p. 69)

3 EXCAVATION PROCEDURE

3.1 Selection of a site; 3.2 Planning an excavation; 3.3 Background research; 3.4 Staff and equipment; 3.5 Excavation strategy; 3.6 Recording; 3.7 Computerised processing of site records; 3.8 Publication; Go back to chapter heading
'Excavation can destroy a site just as thoroughly as ploughing, building construction or natural erosion; the only difference is that destruction by excavation is initiated by people who should (in theory) understand the value of ancient sites. ... Every excavator faces the same ethical question: on what grounds can their action be justified?' (p. 77)
NEW!! Norfolk and Norwich Millennium Project
Norfolk Archaeological Unit has just started a major excavation in the centre of Norwich. The fieldwork will last for 25 weeks from 16th November. The site covers just under a hectare and is adjacent to the Market Place in St Peter Mancroft parish, the richest medieval parish of the city. They have set up a website in concert with the Norfolk & Norwich Millennium Company Limited and the local advisory network for teachers The site will be updated during the course of the excavation (with a digital camera to assist with this) and consists of the following:
* Background
* 'Dig' updates
* Location map
* Aerial Photograph
* Webcam
* Old Photographs
An exemplary presentation (at popular and academic levels) about the excavation of a Roman fort in northern England (Mike Bishop):
'Concangis is a new Web site based upon the 1990-1 Church Chare excavations on part of a barrack block in the Roman fort at Chester-le-Street, Co. Durham. It comprises four main elements:
* A popular account, originally published as a small booklet
* The academic report, originally published in Archaeologia Aeliana
* The daybook kept by the director
* The director's own photographs of proceedings
The text of the first three elements remains 'as is' (the fourth is newly-written), but it has all now been cross-referenced by hyperlinks, so that whilst it is possible to navigate through the various main elements in a linear fashion, you can also dodge around, should the fancy take you. You can, for example, click on a pot drawing to take you to its textual description - where you may find that its context number is in turn linked to the description of that context in the structural report.'
3.1 Selection of a site
'New sites are discovered with growing frequency, but resources remain limited; it is therefore important that sites for excavation should be chosen with care. Since the number of sites is finite, every excavation should form part of a wider programme of research, whether the site is threatened with destruction or not.' (p. 77)
3.2 Planning an excavation
'Even when a site has been selected as a result of a sensible programme of fieldwork and there is a clear reason for the excavation, an enormous amount of research and organisation still remains to be done, irrespective of the period or geographical location of the site.' (p. 80)
3.3 Background research
'No excavation should take place without a careful study of previous work on the site, or without an appreciation of how it fits into a wider landscape. The amount of data that has been collected in advance will determine how well the director is able to draw up detailed plans for the excavation, and to respond to new information that is revealed as excavation proceeds.' (p. 80)
3.4 Staff and equipment
'The ultimate quality of the interpretation and publication of a site depends not only on the skill of the excavator, but also on the comprehensive nature of the recording and preservation of finds; these factors should guide the director's selection of staff.' (p. 81)
3.5 Excavation strategy
'Since even the best-prepared director rarely finds that a site conforms exactly to expectations, the strategy should allow for modifications. Flexibility is important... Interpretation of excavated structures, combined with provisional dating and other observations about the finds, should provide continuous feedback that can help to reinforce, modify or reject the director's working hypotheses.' (p. 81)
3.6 Recording
'Information needs to be recorded with a clear idea of the questions that are likely to be asked about it a later stage, and the archaeologist must be aware of these factors while recording features or artefacts.' (p. 83)
3.7 Computerised processing of site records
'Time devoted to computerised recording is repaid when the director comes to write the excavation report, for a comprehensive site database can be indexed in many different ways to produce specific information sorted into any desired order.' (p. 83)
3.8 Publication
'By the 1960s it was taken for granted that an excavation report would consist of an 'objective' account of the excavated features and structures, followed by descriptive catalogues of each category of finds, along with scientific reports on bones, environmental samples, etc. ... In the twenty-first century, excavation reports may become multimedia experiences, with site records, photographs, drawings and video sequences stored on a single disk.' (p. 83-4)

4 EXCAVATION: SPECIAL CASES

4.1 Camps and caves; 4.2 Waterlogged sites; 4.3 Underwater archaeology; 4.4 Graves; Go back to chapter heading
'It has already been stressed at the beginning of this chapter that archaeology cannot be classed as a 'science' because one of its primary sources of information, excavation, involves the destruction of unique specimens. ... Before tackling the interesting problems involved in excavating and understanding various forms of buildings, it is important to look at other categories of sites that are important in the archaeology of earlier periods or other parts of the world.' (p. 85)
4.1 Camps and caves
'The priority of an excavator is to make exact records of the position of every fragment of bone, flint or other artefacts, for an analysis of their distributions may suggest the functions of different parts of a site and imply relationships between structures and activities. ... Caves occupied from time to time offer much better possibilities for finding stratified deposits, but little in the way of structures; furthermore, their stratigraphy is likely to result from natural weathering and sedimentation as much as from human activities.' (p. 85)
4.2 Waterlogged sites
'The principal difference between 'dry' and 'wet' sites lies in the range of organic finds that will be encountered. Excavation trenches will be more difficult to manage, for it may be necessary to erect platforms suspended above the working surfaces to avoid walking on fragile remains. The greater complexity of structures complicates recording by planning and photography, while additional categories of finds make increased demands on the cataloguing system.' (p. 87)
4.3 Underwater archaeology
'...the guiding principles and methodology of underwater archaeology are identical to those that should be employed on dry sites. However, the additional complexity of the tasks of discovery, excavation, recording and conservation forces directors of underwater projects to take a much more stringent approach to their objectives and ethics. ... Shipwrecks offer rare insights into the technology, warfare and commerce of the past, and individual ships provide a chance to study a range of artefacts that were all in use at a specific date. For this reason they are frequently described as 'time capsules.'' (p. 87-8)
4.4 Graves
'Occasionally the concept of 'time capsules' is extended to burials, for the majority were placed in the ground at a single moment in the past. For an archaeologist, the most informative kind would consist of the skeleton of a dead individual who had been placed into a grave fully clothed, accompanied by grave-goods - a selection of personal items, or gifts to take into an afterlife - that might indicate the deceased's sex, social status and religion, and help to date the burial.' (p. 88)

5 THE EXCAVATION OF STRUCTURES

5.1 The excavation of stone structures; 5.2 Timber structures; 5.3 Other building materials; 5.4 Reconstruction; Go back to chapter heading
'Early excavators cleared stone-built sites without any regard to traces of timber structures, and, in the Near East, only solid stone or fired clay structures were detected on sites whose buildings were constructed mainly from sun dried mud bricks. There is no substitute for experience, based on an understanding of the many processes involved in the formation of an archaeological site - how ruined buildings decay, how occupation layers accumulate, how ditches silt up, etc.' (p. 89-90)
5.1 The excavation of stone structures
'Second only to burial mounds and other major earthworks, stone structures were the easiest form of site for early archaeologists to recognise and excavate. ... Stone was used in areas where it was conveniently available; when it was not, timber, mud brick, or other useful local resources provided alternative building materials. The remains of stone or brick buildings are much easier to recognise than mud brick or timber; as a result, problems of differential survival distort evidence for human settlement in many parts of the world.' (p. 90)
5.2 Timber structures
'Timber only survives where extremely wet or dry conditions have remained constant over a long period. Otherwise, it decays completely, leaving differences in the colour and texture of soil that are only detected by careful excavation.' (p. 94)
5.3 Other building materials
'Along with stone and timber, one of the most important ancient building materials was clay, whether applied directly to wooden walls (wattle and daub), shaped into blocks and dried in the sun (mud bricks: fig. 3.34), or made into bricks or tiles fired in kilns. Building techniques are of course dependent not only on the availability of suitable raw materials, but also on climatic conditions.' (p. 98)
5.4 Reconstruction
'The elaborate nature of excavated remains of buildings is easily underestimated, especially if nothing more than post-holes remains. However, the complexity of joinery and the elaboration of purely decorative detail that survive on many medieval and later timber buildings must have existed in earlier times. Anthropological analogies point in the same direction.' (p. 100)
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