As we’ve already learnt, a context can be described as an action. This action has changed the stratigraphy in some way, and left a trace that archaeologists can see.
Archaeologists will assign a context to each of these contexts, whether that is a cut, fill, deposit etc. It is important to consider how these contexts are formed – has some one dug a hole? Did natural erosion remove the soil? Was it a deliberate fill? Is it a human made surface? Or was it a natural accumulation of material?
Imagine a Roman building. The untouched, naturally occurring soil which the Romans have decided to build on is called the natural. First of all, the Romans create a smooth layer of compacted material, called a preparation layer. They then placed slabs onto this layer to make the hard floor surface. These are the first two human made actions. The building is abandoned, and over the years dust and material is blown in which builds up over the slabs. This is a natural accumulation of material. Years later, someone has come and cut into some of this material to see what lies below. This is another action, which gets another context number. That cut is filled with the another phase of natural accumulation, which fills the cut and lies in a thick deposit. Many, many years later, farmers start to cultivate the land, and the a layer at the top of is disturbed by agricultural activity – the ploughing of the field and the roots from the crops that have been planted. In this example, there are 7 contexts – but an archaeological excavation may come across many more layers.
In order to spot the difference between the layers of soils, archaeologists think of the THREE Cs: Colour, Composition and Consistency. These are ways to describe the material within a context, and every time either the colour, composition or the consistency of the soil changes, a new context is given.
Archaeologists describe the colour in three words – the shade, tone and colour. Shade is whether the soil is light, medium or dark.
Tone is when the colour is mixed with another colour. This is not the main colour of the soil.
Colour is the main colour that you see when you look at the soil.
For example, you can have a light yellow grey soil… a medium orange brown.. a dark grey brown soil.
Archaeologists can use a munsell colour chart to describe colour.
This is what the soil is composed of – i.e. made up of. The soil can usually be categorised into one of these groups: silt, sand, clay. However, there may be other compositions that the soil falls into, such as ash. A lot of the time, the soil may be a mixture between these, such as a sandy silt or a silty sand!
When archaeologists describe the consistency of soil, they are considering how the soil feels. When you’re digging a new context, its best to hold some of the soil in your hands and roll it around your fingers. Think about how it feels and what the soil does. It may crumble, or be very loose that it falls out of your fingers. Maybe the soil is too hard to pick up, and is therefore very compact. It might mould very easily, and you can roll it into a sausage shape. As well as the terms soft, hard and firm, archaeologists may also describe soil as loose, friable, or plastic.
Archaeologists will also think about what is in the context, and these are the components. This does not mean the finds that are in the layer (unless this makes up more than 50% of the layer). For example, there may be lots of big rocks and rubble in this layer – that’s very important to note. Archaeologists can also talk about the inclusions of soil – maybe there is a lot of charcoal, or pebbles in the layer. These details can help archaeologists later with their interpretation of this layer.
When archaeologists record the different contexts, it is very important to note down all features of the change. Sometimes, the soil above this layer may be very similar and it is only a subtle change. They should always take measurements of the length, width and depth of the context, and note down if the layer lies flat or slopes in a particular direction. Every detail will help later when the archaeologist sits down to write their report!