A gradient of 1 in 43 is quite a significant slope, much steeper than
most lowland river courses. It would provide for a pretty erosive
environment under fluvial conditions.
On 11/11/15, Tony Marsh <[log in to unmask]> wrote:
> I agree John but those stripes are only a "mystery of stonehenge" because
> (a) archaeologists uncovered them (looking for transport evidence) and (b)
> the media production staff look for "simple stories" and find them on
> blog-sites. The avenue, over its first straight section, descends at a grade
> of 1 in 43 and, no doubt, in dozens of other places the land surface
> displays such a grade. Chalk deposits were presumably once completely
> uncovered and subject to erosion from sea, wind, rain-water and, possibly,
> heavy water flows from some residual ice-covering. A suitable geo-scientist
> could go and uncover chalk anywhere outside the Heritage Site, without much
> restriction, and analyse a few striated surfaces, relate them to local
> grades and bring out a definitive paper. It's high time this topic gained
> maturity but would that be too boring a proposition to be funded?