Science·phys.org↗·7hOldest known giant rock scallop bead suggests California coastal trade began millennia earlier#phys.org#ScienceSourceRead the original at phys.org0SaveShare📚Add to CollectionNext postWhen you hire film makers instead of marketers.Related postsRare Mars meteorite preserves 1.27-billion-year-old clues to planet's deep interiorphys.orgTiny particles defy action-reaction symmetry to stay in motionphys.orgCosmic filaments help set first limits on dark matter's decay into gravitonsphys.org