Just to add to Rhiannon’s comment. I think it is worth quoting Burl directly as this is a good example of the wit & wisdom of the mighty fella.
“happily, the deterrent of a line of sharp-edged kerbstones at the roadside has ended this conversion of a ritual circle into a napkin ring”.
From Carnac to Callanish
Aubrey Burl
Yale University Press
1993