RABAT, MOROCCO—Science Magazine reports that perforated shells unearthed in western Morocco’s Bizmoune Cave may be 10,000 to 20,000 years older than early shell beads discovered in Israel’s Skhul Cave and Morocco’s Contrebandiers and El Mnasra caves. Similar shell beads have been recovered at other sites in the region and are thought to have been in widespread use. All but one of the 33 thumbnail-sized, oval mollusk shells in Bizmoune Cave were recovered from an ashy layer that also contained stone blades and scrapers, campfire charcoal, and bone fragments from wildebeest, gazelles, and zebras. Dating of stalagmites and flowstones at the same layer as the beads are thought to have formed at the same time the beads were made. The radioactive decay of uranium and thorium in the flowstone indicates it was formed between 120,000 and 171,000 years ago; the researchers suggest the shell beads are at least 142,000 years old. “North Africa has played a major role in the origins of symbolic behavior,” said Abdeljalil Bouzouggar of Morocco’s National Institute of Archaeology and Heritage and the Max Planck Institute for Evolutionary Anthropology. Researchers think shell beads may have been used as personal adornments, to signal clan identity or partnerships, or as gifts to solidify bonds. To read about excavations at the medieval city of Aghmat, go to "Letter from Morocco: Splendor at the Edge of the Sahara."