How the stones of Stonehenge were dragged to the site is of constant fascination. The title of this note was a scribbled message I left myself that I had to remember what I was thinking about late at night when I wrote it.
On Orkney excellent work was done showing how lubricated ground worked better than rollers under a moving monolith - http://brodgar.co.uk/2016/07/10/how-do-you-move-a-standing-stone/ .
They used seaweed but dewey or rotting cut grass on hard ground is like ice as I know to my cost.
Flat stones have a high drag factor and also slide sideways on any cross slope, so just throwing an idea out there would ribbed stones, like the strakes on a boat's hull, reduce friction and provide directional stability?
Could it have been done without the rollers, or sledges and frames we presume were needed?