Stonehenge 181
Image by hrothgar
Stonehenge

Stone shifting 5

Do we know what the climate was like in those days? The winter of 1987 was sufficiently severe to freeze the top 10" of ground (I know 'cos I was digging foundations for my house), so that would have been more than ample to render boggy ground passable. However, in recent years, the ice crust would have been pretty thin. I don't think it would have supported a 40 tonner.

Other considerations:
You can't dig a pit for the stone in frozen ground you'd have to plan months ahead

You'd have to know where all the bogs were in order to stop it from sinking in mud if it thawed!

But it'd be one way of getting it downhill fast...

.o0O0o.