Okay, a little harder then. What was called Stoningland, when, and by whom?
Boring is right in that it is Gondor and is found in a Rohirrim song called the Mounds of Mundburg writen long after the Battle of Pelennor Fields.
We heard of the horns in the hills ringing,
the swords shining in the South-kingdom.
Steeds went striding to the Stoningland
as wind in the morning. War was kindled.
There Theoden fell, Thengling mighty,
to his golden halls and green pastures
in the Northern fields never returning,
high lord of the host. Harding and Guthlaf,
Dunhere and Deorwine, doughty Grimbold,
Herefara and Herubrand, Horn and Fastred,
fought and fell there in a far country:
in the Mounds of Mundburg under mould they lie
with their league-fellows, lords of Gondor.
That's the first half of the song; you can find the rest of it on the last page of LOTR Vol. III, Book V, Chapter 6 entitled 'The Battle of Pelennor Fields'. Give Boring a Cuddly Bear.
One more thing, I've found that if you read Tolkein's songs/poetry/verse out loud it works better than just reading it silently in your head.