Last week the procedure used to produce retents was outlined and this week the next step in the processing of soil samples through flotation is addressed.

The environmental remains from the flot are often readily analysed as there is frequently little else caught in the flot to obstruct their identification. However, the retent is likely comprised predominantly of stone and grit. Within the stones will be the materials that did not float such as bones; artefacts and slag; heavier or waterlogged cereals, seeds or charcoal; shells; hazelnut shell fragments and other obscurer remains such as mineralised organics and heat affected materials.

The significant archaeological and environmental materials must be picked out from the stony retent, identified and quantified. This must be done visually although magnifying lamps and microscopes prove very useful. The difficulty of visually sorting through material of varying sizes can be mitigated by passing the retent through a sieve bank and analysing each sized fraction separately.

Artefacts are a welcome boon to the relative monotony of retent sorting and lithics are fairly common amongst the mundane stones. While not an artefact as such, slag can be found in retents, this can range from metallurgical waste slag to slag type materials produced by the reactions caused by heat on silicates and other materials. Bones are frequently found in the retent and can range from domestic species such as cattle and sheep, which can provide evidence of the domestic economy of a site, to the bones of rodents and other species that may have inhabited a site. These other species can give suggestions as to the site's habitat according to their particular ecological preferences, for instance it can be determined whether a ditch was dry or frequently flooded or whether an area of the site was kept clean or had weeds going unchecked.

Charred organics and uncharred materials such as shell can be combined with the analysis of the flot to provide the standard environmental assessment of the site's environs or changing landscape and domestic or industrial economy. Hints of human preference can also be discerned, for example in the choice of wood species in environments where the selection is not restricted.

Retent sorting procedures are also described in the IAI Environmental Archaeology Guidelines.