Geologists recently discovered marks that closely resemble worm tracks in a piece of sandstone  These marks were made more than half a billion years earlier than the earliest known traces of multicellular animal life
Ttherefore, the marks are probably the traces of geological processes rather than of worms
At the place where the sandstone was found, the only geological processes that are likely to mark sandstone in ways that resemble worm tracks could not have occurred at the time the marks were made.