It’s no pillow-top mattress, but an international team announced today new evidence of Stone Age bedding.
At a sandstone rock shelter called Sibudu that sits high on a cliff above the uThongathi River in South Africa, a group including Boston University scientists analyzed the fossilized remains of what appear to be 77,000-year old floor coverings likely used for sleeping or working. The half-inch thick remains are made up of sedges, rushes, or grasses, with a thin layer of the broad leaves of River-wild quince, a species with aromatic leaves that may have helped keep the mosquitoes away.
Layers of the bedding show signs of being burned, a practice that may have been the Stone Age version of spring cleaning.
“It seems like they intensively cleaned; the idea is they burned the [bedding] to clean them, to get rid of pests. You can imagine, it’s like a stable. After all the straw gets pretty raunchy, insects and bugs and mosquitoes’’ infest it, said Paul Goldberg, a professor of geoarcheology at Boston University who was involved in the research published today in the journal Science. “They probably just periodically burned them down.’’
The Boston University team became involved after Goldberg visited the site in 2005 and collected a large, shoebox-sized block of sediment, wrapped up in plaster of Paris. Through painstaking work, layers of crumbly, powdery sediment were embedded in a hard, clear resin and shaved down to ultrathin slices that could be closely examined under a microscope, where they revealed a surprise — lots of fossilized plant cells.
Francesco Berna, a research assistant professor in the archeology department at BU, used his specialized skills and a type of microscope more often used in crime-scene forensics to examine the mineral content of the samples and to look for signs of human activity. He found the evidence that upper layers were burned.
“You get a better idea how humans transformed their environment inside the shelter,’’ Berna said, because his tools allow him to help tell the difference between natural change and something people did.
There’s no way to know for sure how these patches, which vary in size but generally measured about 3 feet by 10 feet, would have been used. Although the researchers discovered fossilized remains only about a half-inch thick, it would have been 10- or 20-times thicker when it was laid down, Goldberg estimated. Both Berna and Goldberg bristle at the term “mattress,’’ since these patches of floor coverings may have served a variety of purposes.
What’s more certain is that people brought them there. The plants are traditionally found in wet habitats.
“Essentially, there’s just no natural way to accumulate that much stuff without people bringing it in there,’’ Goldberg said.