Feature (archaeology)

A feature in archaeology and especially excavation is a collection of one or more contexts representing some human non-portable activity that generally has a vertical characteristic to it in relation to site stratigraphy. Examples of features are pits, walls, and ditches. General horizontal elements in the stratigraphic sequence, such as layers, dumps, or surfaces are not referred to as features. Examples of surfaces include yards, roads, and floors. Features are distinguished from artifacts in that they cannot be separated from their location without changing their form.

Features tend to have an intrusive characteristic or associated cuts. This is not definitive as surfaces can be referred to as features of a building and free standing structures with no construction cut can still be features. Middens (dump deposits) are also referred to as features due to their discrete boundaries. This is seen in comparison to leveling dumps, which stretch out over a substantial portion of a site. The concept of a feature is, to a certain degree, fuzzy, as it will change depending on the scale of excavation.

Generic feature types

Features specific to certain architecture types or eras such as trilithon for the purposes of this article are not considered generic. Generic features are feature types that can come from a broad section in time of the archaeological record if not all of it. Generic types can include:

  1. Cuts
  2. Re-cuts
  3. Pits
  4. Post holes
  5. Stake holes
  6. Construction cuts
  7. Robber trenches
  8. Walls
  9. Foundations
  10. Ditches
  11. Drains
  12. Wells
  13. Cisterns
  14. Hearths
  15. Stairs and steps
  16. Enclosures
  17. Lynchets
  18. Graves
  19. Burials
  20. Middens
  21. Pit-houses
  22. Fire pits

See also

References

  • The MoLAS archaeological site manual MoLAS, London 1994. ISBN 0-904818-40-3. Rb 128pp. bl/w
Cut (archaeology)

In archaeology and archaeological stratification a cut or truncation is a context that represents a moment in time when other archaeological deposits were removed for the creation of some feature such as a ditch or pit. In layman's terms, a cut can be thought of a hole that was dug in the past, though cut also applies to other parts of the archaeological record such as horizontal truncations like terraced ground. A cut context is sometimes referred to as a "negative context" as opposed to a "positive context". The term denotes that a cut has removed material from the archaeological record or natural at the time of its creation as opposed to a positive context which adds material to the archaeological record. A cut has zero thickness and no material properties of its own and is defined by the limits of other contexts. Cuts are seen in the record by virtue of the difference between the material it was cut through and the material that back fills it. This difference is seen as an "edge" by the archaeologists on site. This is shown in the picture above (Fig 1.), where a half sectioned Saxon pit has had half its backfill removed and we can clearly see a difference between the ground the pit was cut into and the material originally filling the pit. Sometimes these differences are not clear and an archaeologist must rely on experience and insight to discover cuts.

Excavation (archaeology)

In archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is a site being studied. Such a site excavation concerns itself with a specific archaeological site or a connected series of sites, and may be conducted over as little as several weeks to over a number of years.

Numerous specialized techniques each with its particular features are used. Resources and other practical issues do not allow archaeologists to carry out excavations whenever and wherever they choose. These constraints mean many known sites have been deliberately left unexcavated. This is with the intention of preserving them for future generations as well as recognising the role they serve in the communities that live near them.

Excavation involves the recovery of several types of data from a site. These data include artifacts (objects made or modified by humans), features (modifications to the site itself such as post molds, burials, and hearths), ecofacts (evidence for the local environment and resources being used such as snail shells, seeds, and butchered bones) and, most importantly, archaeological context (relationships among the other types of data). Ideally, data from the excavation should suffice to reconstruct the site completely in three-dimensional space.

The presence or absence of archaeological remains can often be suggested by remote sensing, such as ground-penetrating radar. Indeed, grosser information about the development of the site may be drawn from this work but the understanding of finer features usually requires excavation though appropriate use of augering.

Fill (archaeology)

In archaeology a fill is the material that has accumulated or has been deposited into a cut feature such as ditch or pit of some kind of a later date than the feature itself. Fills are an important part of the archaeological record as their formation and composition can throw light on many aspects of archaeological study.

Harris matrix

The Harris matrix is a tool used to depict the temporal succession of archaeological contexts and thus the sequence of depositions and surfaces on a 'dry land' archaeological site, otherwise called a 'stratigraphic sequence'. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. The Matrix was developed in 1973 in Winchester, England, by Dr. Edward C. Harris.

The concept of creating seriation diagrams of archaeological strata based on the physical relationship between strata had had some currency in Winchester and other urban centres in England prior to Harris's formalisation. One of the results of Harris's work, however, was the realisation that sites had to be excavated stratigraphically, in the reverse order to that in which they were created, without the use of arbitrary measures of stratification such as spits or planums. In his Principles of archaeological stratigraphy Harris first proposed the need for each unit of stratification to have its own graphic representation, usually in the form of a measured plan. In articulating the laws of archaeological stratigraphy and developing a system in which to demonstrate simply and graphically the sequence of deposition or truncation on a site, Harris, it has been argued, has followed in the footsteps of the truly great stratigraphic archaeologists such as Mortimer Wheeler, without necessarily being a great excavator himself.

Harris's work was a vital precursor to the development of single context planning by the Museum of London and also the development of land use diagrams, all facets of a suite of archaeological recording tools and techniques developed in the UK which allow in-depth analysis of complex archaeological data sets, usually from urban excavations.

Phase (archaeology)

In archaeology, a phase refers to the logical reduction of contexts recorded during excavation to near contemporary archaeological horizons that represent a distinct "phase" of previous land use. These often but not always will be a representation of a former land surface or occupation level and all associated features that were created into or from this point in time. A simplified description of phase would be that" a phase is a view of a given archaeological site as it would have been at time X".

Examples of phases that would have no associated occupation surfaces are phases of a site that have been horizontally truncated by later phases and only elements surviving of the truncated phase are those that were below ground level and the subsequent truncation at that time. Subsequent or earlier phases are representations in changing occupation patterns and land use over time. Phase is an extremely important concept in archeological excavation and post excavation work. Phasing is achieved by compiling smaller groups of contexts together through the use of stratification and stratigraphic excavation into ever larger units of understanding. The terminology of these sub units or collections of contexts varies depending on practitioner but the terms interface, sub-group, group, and feature are common.

Phasing a site has a slightly different meaning to "digging in phase". Digging in phase is the process of stratigraphic removal of archaeological remains so as not to remove contexts that are earlier in time lower in the sequence before other contexts that have a latter physical stratigraphic relationship to them. Digging a site "in phase" is considered good practice and can be thought of as the process of removing the deposits on site in the reverse order they arrived. Phasing is achieved on site by many methods including intuition and experience but the main analytical tool post excavation is the Harris matrix. Phase is sometimes termed differently depending on practitioner, examples include the term period but in the main phase is universal.

Plan (archaeology)

In archaeological excavation, a plan is a drawn record of features and artifacts in the horizontal plane.

Posthole

In archaeology a posthole or post-hole is a cut feature used to hold a surface timber or stone. They are usually much deeper than they are wide although truncation may not make this apparent.

Although the remains of the timber may survive most postholes are mainly recognisable as circular patches of darker earth when viewed in plan. Archaeologists can use their presence to plot the layout of former structures as the holes may define its corners and sides. Construction using postholes is known as earthfast or post in ground construction.

Relationship (archaeology)

An archaeological relationship is the position in space and by implication, in time, of an object or context with respect to another. This is determined, not by linear measurement but by determining the sequence of their deposition – which arrived before the other. The key to this is stratigraphy.

Reverse stratigraphy

Reverse stratigraphy (sometimes known as inverted stratigraphy) is the result of a process whereby one sediment is unearthed by human or natural actions and moved elsewhere, whereby the latest material will be deposited on the bottom of the new sediment, and progressively earlier material will be deposited higher and higher in the stratigraphy. Such events can be triggered by rockslides, tree throws, or other events which cause the strata of a deposit to be flipped or reversed. In archeological excavations a common cause of inversions in the stratigraphy is the collapse of walls on river banks or other raised mounds where deposits which have been cut through behind the wall prior to collapse slip over the collapsed structure resulting in the structure being under the deposits that originated earlier in time. In this case care must be taken to re-context the slipped deposits so the event of slippage appears in the correct place stratigraphically in the Harris matrix. There are numerous process that can reverse the stratigraphy or more accurately redeposit it. Many rely on slope processes, however other instances where deposits containing material later than overlying deposits occur in such features as drains or hypocaust systems. In these instances a clear understanding of the direction of "UP" and site formation processes is essential. Drains or hypocaust systems often have later material deposited within them during their "use", which may be much much later than either their initial construction or indeed the construction, use and disuse of the floors above them.

Section (archaeology)

In archaeology a section is a view in part of the archaeological sequence showing it in the vertical plane, as a cross section, and thereby illustrating its profile and stratigraphy. This may make it easier to view and interpret as it developed over time.

Single context recording

Single context recording was initially developed by Ed Harris and Patrick Ottaway in 1976, from a suggestion by Lawrence Keene. It was further developed by the Department of Urban Archaeology (Museum of London) from where it was then exported, in the mid-1980s by Pete Clarke to the Scottish Urban Archaeological Trust and Nick Pearson to the York Archaeological Trust. It has become a popular system of recording and planning being used in many countries in Europe and in Lebanon, it is especially suited to the complexities of deep, typically urban, archaeology.

Each excavated context is given a unique "context number" and is recorded by type on a context sheet and perhaps being drawn on a plan and/or a section. Depending on time constraints and importance contexts may also be photographed, but in this case a grouping of contexts and their associations are the purpose of the photography. Finds from each context are bagged and labelled with their context number and site code for later cross reference work carried out post excavation. The height above sea level of pertinent points on a context, such as the top and bottom of a wall are taken and added to plans sections and context sheets. Heights are recorded with a dumpy level or total station by relation to the site temporary benchmark (abbr. T.B.M). Samples of deposits from contexts are sometimes also taken, for later environmental analysis or for scientific dating.

Spit (archaeology)

In the field of archaeology, a spit is a unit of archaeological excavation with an arbitrarily assigned measurement of depth and extent. It is a method of excavation employed without regard to the archaeological stratigraphy that may (or may not) be identifiable at the archaeological site under investigation. The method of excavating in arbitrary spits is most frequently encountered at site excavations which lack any visible or reconstructable stratigraphy in the archaeological context, or when excavating through intrusive or fill deposits.

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