This site is of disputed antiquity. If you have any information that could help clarify this site's authenticity, please post below or leave a post in the forum.
While it is thought that the stone is a natural 'altar' feauture which had significance in the Bronze Age, there is uncertainty about the age of the engravings. The earliest dates suggested are neolithic, the latest are medieval:
http://www.archaeoastronomy.it/archaeo-astronomical_hypotheses_on_some_ligurian_engravings2.htm
(International Rock Art Congress, 1999)
Always grateful to Mr Italo Pucci and Mr M Fenoglio from the Istituto Internazionale di Studi Liguri, to the memory of whom I want to dedicate my little work in this site. Because of them I found this great engraved Sacred Stone. It stands on the northern slopes of Monte Beigua on a bank of the river Traversa and it has to do with a water cult.
It appears as a big blackboard where people wrote through the centuries. So engraved there you'll find prehistoric sacred images together with christian crosses (specially made to exorcise the stone...) together with much more modern engravings, such as people's names. Anyway the oldest engravings are recognisable and still remarkable.