These super little beads were made from natural stone discs found on the shore below, drilled in Mesolithic times. Nab Head was an important Mesolithic seasonal camp.
This link http://books.google.co.uk/books?id=v4Lh0xxgVtoC&pg=PA15&dq=%22nab+head%22&lr=&as_brr=3&sig=dCLlaDyGuvSqNp6w-KmTZ8AJ5RE#PPA13,M1
shows another carved shale artefact - its discoverer, J P Gordon-Williams described it as a 'Duck Head' but this was probably to cover for its obviously phallic appearance. Though it's also been interpreted as a stylised Venus figurine.. but let's face it, men have been scrawling knobs on things for millennia. Does it have to have more significance than that?