A set of shell beads dated from 142,000 and 150,000 years ago, made from half-inch-long sea snail shells, the 33 beads turned up during excavations conducted between 2014 and 2018 near the mouth of Bizmoune Cave, about 10 miles inland from the coastal city of Essaouira. The archaeologists used uranium-series dating, which measure the radioactive decay of uranium, to test the age of the beads and the surrounding layers of ash and sediment. The beads come from two sea snail species: the Columbella rustica, from the dove snail family, and Tritia gibbosula, commonly called the swollen nassa. Each bead had a hole drilled through it, presumably so the ornaments could be hung on strings or clothing, possibly worn as earrings or a necklace. They are similar to other finds on the African continent, but the earliest examples had previously been just 130,000 years old.