Correcting the Record - Stone Erosion

Over at another place * we read: "They claim that since the big sarsens at Stonehenge have hed their edges rounded off since the Neolithic, then so have the bluestones -- and claim that this somehow demonstrates the inadequacy of the glacial transport theory. That argument is fundamentally flawed -- the sarsens have been exposed to weathering for millions of years, and the bluestones have not." 

This is just silly, there is documented proof that the stones at ground level have suffered from the depredations of visitors, vandals and even livestock in the last 400 years, and presumably for the 4000 years before then. It is not the natural shapes of the various stones but the crisp edges from quarrying or shaping that have been rounded that are being noted. 

William Stukeley in 1740 published his detailed account of Stonehenge which included an engraving of Stone 55 showing the tenon still in place. The lintel on the trilithon is still crisp edged as it had not yet fallen.

A recent picture taken from Google Streetview shows that Stone 55 has lost its tenon, all the stones are more rounded and the lintel, back above visitor reach has suffered from two hundred years at ground level. 

(Click any picture for larger versions)

It is also another silly rant in that no one has suggested that some of the bluestones may be naturally rounded boulders that were brought from wales, it is just a strawman argument he is constructing.