In A.E & E.M Dodds’ excellent book ‘Peakland Roads and Trackways’ they mention the stone as marking a change in direction along the Saxon track called the Old Portway.
The Kings Chair outcrop on the NE horizon pointing where to head next.
I’ve read elsewhere that the small cross may have been an attempt to christianise an ancient pagan stone...Although on the other hand the cross may indicate the stone’s close proximity to the parish boundary and was included in the Rogationtide perambulations as elsewhere in the Peak.