Archaeology: An Introduction - 4th Edition 2002
The Online Companion: updated November 2007


CHAPTER 3 : Excavation

>> CHAPTER OVERVIEW

3.1. THE DEVELOPMENT OF EXCAVATION TECHNIQUES

3.2. THE INTERPRETATION OF STRATIFICATION

3.3. PLANNING AN EXCAVATION

3.4. EXCAVATION STRATEGY

3.5. RECORDS, ARCHIVES AND PUBLICATION

 

 


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3.1. THE DEVELOPMENT OF EXCAVATION TECHNIQUES

3.1.1. The concept of stratification

3.1.2. General Pitt Rivers (1827-1900)

3.1.3. Developments in the twentieth century

3.1.4. Mortimer Wheeler (1890-1976)

3.1.5. From keyhole trenches to open areas

 

3.1. THE DEVELOPMENT OF EXCAVATION TECHNIQUES

Before 1900, few sites were explored by removing distinct layers and recording objects found together in them. The exceptions were mainly investigations of caves with early prehistoric occupation by excavators with a background in geology who were familiar with the concept of superimposed layers (strata) containing distinctive fossils. Finding artefacts made by humans together with bones of extinct animals was vital for proving the depth of prehistoric time. Historians and art-historians were more interested in finding inscriptions, documents or works of art; these could be recovered without paying attention to the contexts in which they were found.

3.1.1. The concept of stratification

Modern excavators study the stratification of a site to guide the recording of individual deposits (with their associated finds) and to place them correctly in the overall sequence.

3.1.2. Pitt Rivers (1827-1900)

The progress made in the late nineteenth century is exemplified by Augustus Henry Lane Fox (later known as Pitt Rivers). He had already played an important part in the development of the typological study of artefacts, and conducted fieldwork and surveys in England and Ireland; excavation only became Pitt Rivers' major activity after he inherited a large tract of Wessex, one of the richest archaeological areas in England.

3.1.3. Developments in the twentieth century

Three indispensable elements of excavation emerged by the beginning of the twentieth century: horizontal observations were combined with accurate recording; vertical sequences were increasingly important; systematic attention to all classes of finds was the newest element.

3.1.4. Mortimer Wheeler (1890-1976)

Mortimer Wheeler, whose outlook and methods seem (like those of Pitt Rivers) to reflect his military background, combined horizontal and vertical excavation with stratigraphic recording of finds in his work from the 1920s.

3.1.5. From keyhole trenches to open areas

Keyhole excavation was carried out extensively in Roman military archaeology by Ian Richmond, who produced overall plans of many forts and fortresses in northern Britain by the judicious excavation of small narrow trenches, carefully placed to check critical details of the fairly predictable layout of their internal structures.

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3.2. THE INTERPRETATION OF STRATIFICATION

3.2.1. Dating stratification

 

3.2. THE INTERPRETATION OF STRATIFICATION

The principle of superposition holds that layers of soil (or any other material) are deposited in chronological order, with the oldest at the bottom. Stratigraphic excavation is based on this principle, whether it involves a long sequence of deposits or a unique relationship between two intersecting ditches.

3.2.1. Dating stratification

In practice stratification rarely consists of horizontal layers, but is complicated by disturbances by human and natural activity. Independent evidence must be found to provide date ranges for a stratigraphic sequence.

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3.3. PLANNING AN EXCAVATION

3.3.1. Excavation, ethics and theory

3.3.2. Selection of a site

:: Types of archaeological investigation

3.3.3. PPG 16

3.3.4. Background research

:: Staff and equipment

:: Finds and environmental work

 

3.3. PLANNING AN EXCAVATION

 

This will operate alongside MAP2 - Management of Archaeological Projects for EH funded projects until the production in 2006 of:-

3.3.1. Excavation, ethics and theory

Excavation can destroy a site as thoroughly as ploughing, building construction or natural erosion; the difference is that it is initiated by people who are conscious of the significance of ancient sites. This brings responsibilities that are a combination of common sense and ethics, but have been expressed formally in the Code of Conduct of the Institute of Field Archaeologists (IFA), an organisation of archaeologists in Britain that attempts to set standards for professional work.

3.3.2. Selection of a site

One archaeological site might attract attention because it is particularly well preserved, another because it is threatened by destruction; are these good reasons for excavation? The answer depends upon whether you think that a picture of the past can be built up from a gradual accumulation of independent observations, or whether individuals or organisations should design coherent research strategies.

----- Types of archaeological investigation

The IFA produced updated Standard and guidance statements in 1999 which defined a series of levels of investigation that an archaeological site might receive, from entirely non-intrusive examination to full-scale excavation.

3.3.3. PPG 16

PPG 16 probably means little to anyone who is not engaged in professional archaeology in Britain. However, Planning Policy Guidance 16: archaeology and planning (1990) has transformed the way in which most excavation is conducted in England by embedding it in the wider processes of planning and development.

3.3.4. Background research

Excavation should not begin without prior assessment and evaluation of the kind outlined in the IFA's definitions. The more data that can be collected in advance, the easier it will be to draw up detailed plans for the excavation - and to respond to new information that is revealed as it proceeds.

----- Staff and equipment

The number and nature of staff involved in an excavation are directly related to its size, resources and complexity; on small sites, many tasks may be performed by an individual site officer. Some basic tasks normally require specialist staff, and recording is the most important.

----- Finds and environmental work

An excavation that produces a large quantity of finds will also require an assistant to manage their cataloguing and storage, with sufficient helpers to clean and sort pottery and other materials

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3.4. EXCAVATION STRATEGY

3.4.1. Forms of sites

:: Camps and caves

:: Permanent settlements

:: Cemeteries

3.4.2. Excavation in special conditions

:: Wetland archaeology

:: Underwater archaeology

3.4.3. Contexts and features

:: Banks and mounds

:: Ditches and pits

:: Surfaces and working areas

3.4.4. Structures and materials

:: Stone

:: Wood

:: Other building materials

:: Standing buildings

:: Reconstruction

 

3.4. EXCAVATION STRATEGY

During an excavation individuals using hand-tools such as trowels make continuous observations and judgements about the texture, colour, and significance of soils, deposits or features. In addition, they must be able to recognise all kinds of finds, from solid stone or pottery and fragile corroded metal to the faint discolourations left by organic materials that have decayed away completely.

3.4.1. Forms of sites

Different forms of sites (temporary or permanent, domestic or ritual etc.) have different implications for excavators, while environmental conditions (such as wetness or aridity) affect the nature of deposits and the survival of artefacts and structures.

----- Camps and caves

Early prehistoric settlements associated with hunter-gatherers were predominantly temporary, and frequently made use of natural rock-shelters or caves. Excavation is likely to focus upon identifying activity areas, and establishing whether occupation was regular or intermittent.

----- Permanent settlements

A sedentary lifestyle is a very recent innovation in human history. It began at different times in different parts of the world, normally when farming came to replace hunting and gathering as the predominant means of subsistence. Sites where people actually lived, as opposed to carrying out purely ritual or industrial activities, remain the most common focus for archaeological excavation.

----- Cemeteries

In many societies graves were placed together in cemeteries, sometimes attached to temples or churches, but the dead were not always separated from the living, and burials may be found in or around houses.

3.4.2. Excavation in special conditions

Temperate zones of the world, including Europe and large parts of the North and South American continents, have been characterised by intensive arable farming for many centuries - with predictably destructive effects on archaeological sites.

----- Wetland archaeology

The growth of ecological perspectives drew attention to the potential of investigating waterlogged sites, and led to the 'classic' investigation of a Mesolithic site at Star Carr in Yorkshire. This tradition continues in Britain, and includes major work prompted by 'rescue' archaeology, such as the Somerset Levels project; wetland archaeology also thrives in many other parts of the world.

----- 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 resources and safety.

3.4.3. Contexts and features

----- Banks and mounds

Many positive features are created during the course of managing a landscape, such as cultivation ridges in fields, field-walls, hedges and other boundaries, or piles of stones heaped up at the edge of cultivated land. Some ancient landscapes contained dozens of substantial mounds and banks created for burials, ceremonial processions, and other ritual or social purposes.

----- Ditches and pits

The normal excavation method is to empty a pit in such a way that its section may be recorded, ideally on more than one axis, in order to study the way in which it was filled and to recover artefacts and environmental samples that will help elucidate its function as well as providing dating evidence.

----- Surfaces and working areas

What was important to the digger of the pit or ditch was the size and shape of its empty internal space, whether designed to provide defence, contain water or accommodate rubbish. It might have remained open for a considerable length of time, and this may possibly be detected by weathering of the sides, but the surface has no physical existence, since it is simply the interface between the ground and the filling of the feature

3.4.4. Structures and materials

Information gained from the excavation or analysis of buildings is of enormous value; background research should include awareness of the great variety of techniques and materials used for constructing buildings so that important traces are not overlooked through ignorance.

----- Stone

The use of stone for construction does not necessarily imply higher technical ability, wealth or social status than other building materials. Stone was used in areas where it was conveniently available; when it was not, timber, mud-brick or other building materials were employed.

----- Wood

Unless extremely wet or dry conditions have remained constant over a long period wood decays completely, leaving differences in the colour and texture of soil that are only detectable by careful excavation

----- Other building materials

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-brick), or fired in kilns to make non-perishable bricks or tiles.

----- Standing buildings

The idea of preserving representative examples of old buildings only became enshrined in planning policy in the late twentieth century, perhaps because urban renewal had damaged historic cities on an unprecedented scale - frequently removing old buildings that had survived two World Wars in Europe.

----- Reconstruction

An excellent way of increasing understanding of an excavated building is to create a scale model or reconstruction drawing. Some information may be particularly helpful, notably the size and strength of foundations, pillars and walls.

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3.5. RECORDS, ARCHIVES AND PUBLICATION

3.5.1. Recording

3.5.2. Publication

 

3.5. RECORDS, ARCHIVES AND PUBLICATION

3.5.1. Recording

An increasing demand for objectivity and accuracy, combined with the complexity of (for example) a large open-area multiperiod urban excavation, led to the design of pre-printed forms for recording each context. These allow the director to impose standardised recording methods in advance of excavation that remove control from supervisors, who no longer record observations in a rather personal way, but simply manage the procedures necessary for filling in forms.

3.5.2. Publication

As the amount of information produced by excavation has increased, so too have expectations about its quality and detail. Now that single-context recording is well established and computerised databases are in common use, it is possible for an excavation to be recorded almost entirely in digital form.

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