The legend of Carnac which explains these avenues of monoliths bears a resemblance to the Cornish story of ‘the Hurlers,’ who were turned into stone for playing at hurling on the Lord’s Day, or to that other English example from Cumberland of ‘Long Meg’ and her daughters.
St Cornely, we are told, pursued by an army of pagans, fled toward the sea. Finding no boat at hand, and on the point of being taken, he transformed his pursuers into stones, the present monoliths.
The Saint had made his flight to the cost in a bullock-cart, and perhaps for this reason he is now regarded as the patron saint of cattle.
From ‘Legends and Romances of Brittany’ by Lewis Spence (1917?), which you can read on the Sacred Texts Archive.
sacred-texts.com/neu/celt/lrb/index.htm