It is alleged that, in 1654, a stone tablet was recovered from All Hallows Well close to the River Blakewater in the centre of Blackburn, commemorating the dedication of a temple to the Helleno-Egyptian deity Serapis by Claudius Hieronymus, legate of the Legio VI Victrix.
I’ve heard it likely that the Roman religious activity suggests that this site was sacred in the prehistoric period. Its dedication to “All Hallows” might also suggest this.
Sadly, nothing remains at present bar a commemorative plaque nearby describing the 1654 discovery.