There are only three of these shells — discovered in Israel and Algeria — so there’s no way of knowing for sure, but they do seem to confirm earlier evidence that human beings were decorating themselves way before archaeologists thought they were.
The archaeologists also pointed out that the Israeli and Algerian sites were so far from the seashore that the shells were most likely brought there intentionally for beadworking. A study of modern shells of similar snails, they noted, determined that the chances that the holes occurred naturally were extremely small.
In the journal report, the research team led by Marian Vanhaeren of University College London and Francesco d’Errico of the National Center for Scientific Research in Talence, France, concluded, “These beads support the hypothesis that a long-lasting and widespread beadworking tradition existed in Africa and the Levant well before the arrival of anatomically modern humans in Europe.”
There’s another excellent article on the find here.