Lady Jane Rufton is the name given by Brigadier Gerard in his memoirs (as edited by Arthur Conan Doyle to the sister of Lord Rufton, the English peer into his custody Gerard, a prisoner of war, had been placed between being granted his parole and repatriation to France. Lady Jane was the wife of Lord Dacre.
In his article The Two Lord Ruftons, Philip José Farmer points that Gerard habitually misunderstood the correct way to address members of the British aristocracy, and that the evidence of the Sherlock Holmes story The Disappearance of Lady Frances Carfax is that the family of Lord Rufton bear 'Carfax', not 'Rufton', as their surname. Lady Jane's maiden name would therefore have been known as Lady Jane Carfax, not Lady Jane Rufton, prior to her marriage. It should be noted that in Farmer's article, the Lord Rufton in the the Sherlock Holmes story is said to be the grandson of the Lord Rufton in the Gerard story.