The main question with regard to megalithic art (petroglyphs from neolithic times) is of course; what does it mean? Lots of books are discussing this subject, like the book The stars and the stones of M. Brennan and the book Irish symbols of 3500 BC of N.L. Thomas
It seems that the buildings (like Newgrange,
etc.) which have art on its stones, could be aligned to mark some
moments in the year. Possibly like a kind of calendar (remember there
then no clocks, agenda's and others means to mark time). So these
were perhaps used as big
sundials and/or libraries of knowledge.
The pictures carved in the stones (petroglyphs) that make the walls, could indicate towards astronomical knowledge. But the question still remains what knowledge do these pictures precisely represent, if they represent knowledge!
To help generate ideas, please look at the ideas of the below
people (in order of publication date, more books on this subject are
in my virtual library). The definition
terms used within my web site can be found on this
It are summaries (so made under my own responsibility) of some books on megalithic art. The summaries look at: motifs, symbols, alignments/directions, calendars, interesting issues, questions to authors, etc. Myths are not yet covered in the summaries (which could of course be important for understanding the art)!
My ideas, partially made up from the above ideas, can be
on this page.