The Iceman Cometh

As many of you know, for a long time Gavin has held the peculiar view that the stones at Stonehenge were moved during winter--when the ground was frozen hard and anywhere water fell, slick ice would form. Even large stones would slide over ice, and slide quite easily at that. Not only that, but instead of building rickety scaffolding from the very few trees available on the chalk downs, workers could build ice banks / ramps so that the stones could be pushed up and tipped to assume their intended vertical positions; with equal ease the lintels too could be slid up and into place.
The other day, while we watched a documentary on Egypt, Gavin was intrigued to learn of a tomb painting showing blocks being transported for the building of pyramids. Those blocks were coated with a white substance, and that tomb painting clearly depicts a lone worker pushing such a block along.
The natural question then is: What was that white substance?
If we look at the map of Egypt and north Africa, we see that the Blue Nile flowing northward through Khartoum becomes simply the Nile as it flows from the mountainous region to the south.
Even so close to the Equator, some of those mountains have a perpetual ice cap. Admittedly it's a long way from them to Gizeh, but boats could have loaded ice and simply floated down the Nile; thus ice would have been available on which to slide the stones. Gavin likes this theory a lot better than he likes the various weird constructs of the archaeologists--including the latest, making hundreds of round stone balls and of course wood tracks to run the immense stones on Stone Age ball bearings.
The ice-movement theory would also account for the movement of blocks in South America to the present-day ruins of Machu Picchu ... never mind how the skill might have crossed the Mediterranean, the Atlantic, and the South American continent at its broadest point.
Anyone who has lived in rural areas of a northern European nation or in middle America knows that winter is the ideal time to move heavy objects. Any farmer knows this and makes use of it when he wants to re-set, for instance, his hog pens. And surely the people who built the great stone monuments would have been smart enough and close enough to Nature to use this, Her gift.
In looking at the thermocline, we find that during the time when Stonehenge (for instance) was built the climate was a couple of degrees colder than it is today; and although a couple of degrees doesn't sound like very much, it does in fact mean that the ground remained frozen for a longer period than it currently does.