Well no pebbles thrown so far - let alone standing stones!
So below is what I think Tolkien may have modeled the shallow hill with its standing stones upon. It’s Ireland over France that I’ve selected.
The Historic Hill of Tara, County Meath, Ireland
Two rimmed mounds at the top of the Hill of Tara and a Barrow
(Mound on right with round saucer-like inner bowl,
Mound on left with the ‘Stone of Destiny’, Barrow – upper right corner)
Lia Fáil: The ‘Stone of Destiny’ – atop Hill of Tara
So I think the hill of the novel was not meant to be an identical copy – but one whose resemblance was unmistakably akin to the knowledgeable. The shallow Irish hill in County Meath, I have a feeling, was ‘slightly’ modified in terms of architectural features for the tale. Instead of two distinct mounds at the top, Tolkien merged them together to make one:
“… shallow saucer with a green mounded rim.”
– The Fellowship of the Ring, Fog on the Barrow-downs
The ditches and outer humps were discarded while the hollow turfed circle at the hill’s summit was kept. In the middle of the hollow Tolkien might well have placed the equivalent of Tara’s ‘Stone of Destiny’.
“It was shapeless and yet significant: like a landmark, or a guarding finger, …”.
– The Fellowship of the Ring, Fog on the Barrow-downs
The Tara stone does have a finger-like shape. Though I’m perplexed as to how anything finger-like could be termed ‘shapeless’.
Any massive objections so far?