Human occupation sites, such as caves, often carry a natural record of tens of thousands of years of history in the layers of dirt on the floor.
Archaeologists have often missed some of the most interesting artefacts lost or discarded by cave dwellers because they are so tiny.
An archaeologist tole me they typically sift the soil from an occupation site through 6mm and 3mm sieves on site, and then examine the dirty gravel.
She says they get a much better result when they “wet sieve” in the laboratory as it is easier to find artefacts in clean gravel.
Science Network WA first published this story. The North West Telegraph and the Pilbara News republished it.