I'd say considerably off the spiral path and even more off topic; so let's take a few steps back.
Silbury was constructed some four and a half thousand years ago as a five-stepped 'pyramid' (why five-stepped?) from local calcium carbonate material; that material would have appeared stunningly white when first cut and stacked. Silbury then, and for several thousand years thereafter, was the largest manmade structure in Europe, visible not only from the oldest road in Europe (the Ridgeway) but also from an almost inexplicable number of other places (why so many places?).
I struggle to find a modern parallel to Silbury - the only one (and not a very good one) is the Statue of Liberty (the List shudders). I know, Liberty's a lousy parallel but I can't think of another one right now and it's late and I'm tired so it'll have to do. But imagine for a moment that you're a traveller on the Ridgeway four and a half thousand years ago. For a couple of days or more you've been tramping the track, maybe with family and friends on a pilgrimage to Britain's Mecca; or maybe you're travelling alone with a bag or two of things to trade; or maybe you're a Tsuchitala with a tale or two to tell. Maybe you were coming into the Avebury arena from some other direction but, anyway, there in the distance Silbury appears - shining out of the morning mist or the evening haze bigger and brighter and more stunning than anything you've ever seen before or ever likely to see again (French horns here please and a picture of Manhattan Island in the fall ;-).
Contrary to what I've just said I'm not generally given to romanticisim, but the sight of a gleaming white Silbury, four and a half thousand years ago, set in a soft and sensual landscape would have taken your breath away (it does so even now). Did Silbury originally rise to a point? Hell, I don't know, but my gut instinct tells me that it didn't. My gut instinct also tells me that Sbury was not only a place to marvel at but was a place to gather... but who knows? Did Silbury have a path (spiral or otherwise to its summit? My gut instinct tells me that it did, and the fact that Silbury was stepped doesn't really make any difference - you can still have a spiral path whether a structure is stepped or not stepped.
Was Silbury intentionally grassed over or allowed to naturally become grassed? Well, as a conservator, that really is an interesting one. My gut instinct tells me that it was never intentionally grassed over but perhaps there was a wisdom at work here that is even more stunning and even more cunning than the one that lay behind Silbury's original conception and construction - for what better way to carry this place of wonder into the future than to let nature cover it gently over in a robe of greenery...
Littlestone also exits rambling... what was the question again?
