4.1 What the archaeological record looks like in the Ground

If the responsible artefact hunter is to  record the bits of the archaeological record destroyed in removing artefacts in collection-driven exploitation of a site, obviously they need to know what it is they are looking for, in other words, what the archaeological record looks like.

At this point, many textbooks would show the reader a section or two showing the superimposed layers ("like a cake"). But that actually is not the way the stratification of a feature are actually encountered in the field. The suggestion that it is the section that is always paramount in the recording and interpretation of a site is a very damaging one. This is despite the prevalence of single-context recording in the standard excavation methodical toolkit for over half a century.

The main manner in which the stratigraphical units of a site are met is from above, from the working surface. The first point that this raises is that this should at all times be kept clean of loose soil, trample etc. After the covering layers (turf, leafmould, asphalt, topsoil, blown sand, modern dumped material etc) have been removed, the surface is vigorously cleaned by shovel shaving, hoeing or trowelling over the whole area to reveal a surface that appears to contain stratified layers, 'hard' elements (such as walls and cobbling) and/or infilled features. Then it will look a bit like this:

Excavations in land off Meadowlands Avenue, Barrow-in-Furness,
Cumbria (courtesy Greenlane Archaeology Ltd.)

Here, the importance of cleanliness will be appreciated. In this exposed clean surface a number of features can be seen. On the right, the light coloured layers may well be the sterile subsoil (sometimes called in archaeological parlance 'the natural', but that term is not very satisfactory)and the straight edge running away from the camera in the foreground might turn out to be the edge of a cut feature filled with the light brown soil, and its line seems to continue into the rear planes. A transverse line of greyish soil separating the  two areas of 'natural' seems to be another linear feature running across the trench. In the rear on the left can be seen a pit and a narrow gully with dark grey fill. Excavation should begin by removing the latest layer... which is?

Of course appearances can be deceptive, it is not clear from this angle whether there are other features dug into the light brown 'fill', it might need another clean and also observations under different conditions of moisture to clarify what is really happening. also it is not unknown for layers that appeared originally to be the latest (lying on top of the others) is on excavation found to go under them...

In the surface therefore are visible a number of units of stratification (layers, features) and the interfaces between them, as well as the effects of various natural processes that have affected the soil deposits.

Probably the most noticeable will be the 'hard' features such as walls and hard metalled surfaces. These will be recorded before a decision is taken whether to remove them to access any stratification preserved below them.

Towcester Roman walls emerging (Cotswold Archaeology)

On many other sites, the main type of features found will be pits, postholes and ditches. These can be recognised by the difference between the soil filling them and the material they were dug through. The Simon Fraser University Museum of Archaeology and Ethnology 'Forensic Archaeology' webpage has a succinct explanation of how archaeological features (in this context graves) are archaeologically visible:

Soil is made up of organic and mineral components that form through natural processes. Soil typically forms over very long periods. People affect the natural soil when, for instance, they plough it to plant crops, or cut into it to construct buildings. When people interrupt naturally formed soil, they change how solid it is (its compaction). The same principle applies when a person digs a grave to bury a body. Loose, less compact soil suggests that it has been recently disturbed, typically by human or animal activity. Sometimes contrasts in soil compaction can be seen but archaeologists using tools such as a shovel or trowel can usually feel the difference in soil compaction, which tells them where the naturally formed soil has been disturbed.Soil compaction changes with the size of the soil grain. Sand grains are larger than silt grains, which are in turn larger than grains of clay. Soil compaction can naturally differ greatly from one area to another, but recent clandestine or unmarked graves show soil looser than the naturally formed soil that surrounds them. The same principles apply for more ancient archaeological features and activity, but over time the compaction of the disturbed soil generally appears more like the undisturbed soil around it.

In the images above, contrasts in soil can be seen between
the darker-coloured, looser soil that is filling a grave
and the lighter, more compact soil that has not be disturbed
(Simon Fraser University Museum of Archaeology and Ethnology).

In other cases, the feature is more clearly visible in the excavated surface because the soil in it is discoloured due to contained material, such as charcoal and stones:

Hearth at Church Street, Maidstone (Canterbury Archaeological Trust)

Tamara Kroftova comments:

"Since one cannot make any kind of archaeological observation in order to record the context of a retrieved find, first it has to be seen. Therefore in responsible artefact-retrieval, conditions have to be created for those observations to be made, otherwise removing the artefact blind from any context is just wanton destruction.

In a small hole dug blindly down with a spade - like when 'metal detecting', even if the bottom of the hole is well-lit and carefully cleaned, the person removing archaeological objects from the ground will be unable to see its place in the archaeological record. In many cases during 'metal detecting', photos and videos show that the bottom of an artefact-extraction hole is typically dark, obscured by loose soil falling from above  and the artefact hunter is groping about blind - often guided by an electronic pinpointer rather than any observations of the nature of the soil that is being dug through".