This makes for a good read…

http://www.english-heritage.org.uk/caring/conservation-projects/silbury-hill/

And this is interesting considering our discussion on the original path…a flight of stairs??!!

‘The present pathway up the mound is a useful archaeological indicator, for its position has not changed at all since John Aubrey - often regarded as the founding father of analytical field survey - illustrated it during the 1660s. All features that the path overlies or cuts through must therefore be earlier. One earthwork that the path post-dates is a broad but low bank that rises from the terminal of the western causeway almost to the summit. It is conceivable that this marks the line of a hedge that once subdivided the mound, but it could represent an ancient route to the summit - perhaps even the remains of a flight of stairs’.