Archeology is a destructive process, once a site is dug it is impossible to return everything to its original position. As such all material must be recovered and recorded to gather the most accurate information about the sites past in hopes of understanding it. The first hindrance to this is preservation. An artifact or feature’s material effects it’s preservation and thus whether or not it is found and recorded. For example, because of fluctuation in weather, wet and dry seasons, organic materials like wood do not preserve well other than in exceptional circumstances (of which Eleon is not one). Stone, pottery and some other inorganic materials tend to fare better in terms of preservation but are still susceptible to similar degree of visibility bias and surface weathering. While these situations are out of an archeologists control, choices they make while excavating can affect what they recover. Their choice of recovery methods, ie how material is collected will have a large effect on what information they get out of a site. Some things are more likely to be found depending on the methods used. Big, shiny, “important” artifacts are generally recovered but as the aim is to recover the most physical information possible, all material, no matter how small and insignificant it may seem, should be saved from the spoil pile.
Hand Collecting: Hand collecting entails recognizing a find in the soil and picking it out while excavating. Mid-large sized pottery sherds, large bone/shell fragments, some worked stone fragments, and significantly sized full artifacts are often recovered in this way. In addition, artifacts that stand out from the soil and are not covered in dirt, ie material that is shiny, coloured, or an obvious shape are also recovered easily with this method. In a number of Eleon’s trenches it is not uncommon to have bags of sherds at the end of a day’s work that have been collected this way. However, when hand collecting, smaller fragments and finds are often missed. People are generally biased to look for the big “important” finds without knowing it and because of the need to be efficient, do not have time to carefully sift through all the soil they move. With short seasons it is not realistic to carefully screen every bit of soil excavated. Regularly this isn’t a big deal as what is needed to date and learn more about the site is generally noticed and picked up. Tiny, nondiagnostic pottery sherds are not as useful to study as nearly complete vessels. However, when things like glass or human remains are found or if other rare occurrences such as tombs arise there is a need to be extra careful to avoid missing small but valuable materials. Additionally, botanical information is not acquired by hand collection as it is difficult to separate them from the soil by use of hands alone.
At Eleon, dry/wet sieving is primarily used in special circumstances (like tomb excavation, glass/metal finds etc) to increase the amount of material recovered. Flotation is used in the recovery of botanical remains that can be analyzed to discover more about the site’s flora in antiquity.
Dry Sieving: Dry sieving is an archeological technique where soil is placed on a wire mesh screen in a frame. The frame is shook to allow dirt to separate from artifacts and fall through the mesh into a wheelbarrow. The remaining soil is then looked through and bagged accordingly. This process makes clumps of dirt that should be broken up to look for sherds inside more obvious and the removal of dirt makes finds stand out better than if they were on/in the ground. However, it is not only dirt that falls into the wheelbarrow. The mesh can let small but important finds like lithic flakes and bone fragments through and does not collect most botanical remains as they too slip through the mesh. As with most cases, there is also a possible degree of human error. You may know the process backwards and forwards but if you do not know what glass found on site looks like you may mistake it for a rock if it is covered in dirt.
Wet Sieving: Wet sieving adds water to the process and can be used in concert with dry sieving to further clean material and collect smaller pieces that may have fallen through. It fully removes dirt and makes artifacts/finds more apparent. In wet sieving a stream of water from a hose is passed over soil sitting on a wire mesh to clean it. When dealing with human remains a second, tighter mesh is often added on top of the wire mesh frame. The remaining material is then carefully examined and any pottery, bone etc is removed and bagged. When finds are small enough to pass through the mesh in dry sieving, or remain covered in dirt, they are often caught during wet sieving, especially if the second mesh is used. As with hand collecting and dry sieving some things are still too small and slip through the mesh or our attention. Also, like the above two methods above, botanical remains are not recovered in this way.
Flotation is an archaeological technique used on site to recover botanical remains from soil samples. Trench supervisors chose to send soil samples from areas where there may be a wealth of botanical information to be accessed. Once collected the samples are sent down to the “flotation station” where the drum and water spigot are located. The drum has a spout that connects to a hose just below a grate where fabric mesh is placed to hold the soil sample. There is a lip at the top of the drum where water can spill off, hitting another piece of mesh just below it. The soil sample is placed on the mesh screen inside the drum and water is pumped in, gently dissolving the dirt and agitating the material left behind. Because of their low density, plant remains (the light fraction) float to the surface and spill onto the outside mesh screen while heavier objects (rocks ( microliths), tiny pottery sherds, bone fragments etc) are left on the inner mesh (the heavy fraction). Once the heavy fraction is clean the drum is drained and both mesh screens with the fractions on them re removed. The fractions are then left to dry in the hot sun with their associated tags. At the end of the day the light fraction is folded up and placed inside the heavy fraction’s mesh. The mesh is then gathered up like a gift basket and hung from twine in a tree. In the next day or so, once fully dried, the bundles are removed and sent home to be analysed/packaged by team members there.
These are some of the methods used at Ancient Eleon (and at other sites) to give archeologist the best possible chance of recovering archeological material. I have been lucky to have learned how to use all of these methods at my time at Eleon so far. Thank you to the directors and senior staff for this learning opportunity.