More limestone erratic blocks blocks in Wiltshire

 The two Berwick St James stones, now on either side of a roadway

A reminder that the "Meaden Cobble" is not the only piece of limestone found on the downs or Salisbury Plain.  There are many pieces assumed to have been used as packing stones at Stonehenge itself -- not sure whether anybody has actually counted them........  

But the most intruguing occurrences are the Berwick St James stones -- which may originally have been one larger slab, used as a footbridge across a local stream.   There is no archaeological context, but for years it was assumed that these stones were related to the Altar Stone at Stonehenge.  More recently it has been discovered that there is no geological or petrographic link, and that the two stones in question are limestone, not sandstone. They are referred to as peloidal packstone and packstone/grainstone.   The stones have a somewhat unusual knobbly or lumpy surface.  This specific "impure" limestone is rare in the Lower Jurassic period; there may be a source from the Middle or Upper Jurassic.  The nearest feasible natural source for this rock type is near Tisbury, approximately 22 km (14 miles) southwest of the Stonehenge area.

See Thorpe and Williams-Thorpe, 1992.

The stones are erratics, and they have clearly not been carried in to this site as building stones or road metal!  Maybe they were once (as a single slab) used as a standing stone somewhere in the vicinity?  The heavily pitted surface suggests very long exposure to the elements and to loss of mass due to solution........

Here is a 2024 somewhat speculative comment from Andrew Collins on Facebook:

https://www.blogger.com/blog/post/edit/1228690739485734684/261207925045772628

Great new video on the hunt for the second Altar Stone at Stonehenge with Hugh Newman and myself. All the evidence seems to point right now to two standing stones, partially buried, at a place called Berwick St James just a couple of miles west of Stonehenge. These stones are strongly suspected to have been fragments of a single huge megalith 15 feet in length, matching very well the existing Altar Stone. Critics of the Berwick St James stones being the second Altar Stone point out it is made of limestone and no limestone was ever used at Stonehenge. Thus the Berwick St James stones are a red herring. However, working with Stonehenge expert Simon Banton we have uncovered incredible new evidence that limestone was indeed used at Stonehenge. More than this various fragments of limestone were found in the exact vicinity of the stone hole now thought to have contained Altar Stone 2. All is revealed in a new article being prepared right now.

The taller of the two Berwick St James stones -- note the pitted and lumpy surface

 Further developments awaited -- suffice to say, for the moment, that the idea of a second Altar Stone is not universally accepted...... 

Then there are the Shelving Stones, near Avebury. They were mentioned some years ago by Pete Glastonbury.  Most of the stones are sarsens, but there is also oolitic limestone at the site.  (I haven't been able to find a photo).    Current archaeological theory -- which may of course be completely wrong -- suggests that this limestone was deliberately transported 10–12 miles from distant outcrops.  The oolitic Limestone was identified by Mike Pitts and later confirmed by Jim Gunter.