This is her article from thepeerage: "Lady Sybil Mary St. Clair-Erskine F, #71080, b. 20 August 1871, d. 21 July 1910 Consanguinity Index=0.0%
Lady Sybil Mary St. Clair-Erskine was born on 20 August 1871. She married Lt.-Col. Anthony Mildmay Julian Fane, 13th Earl of Westmorland, son of Colonel Francis William Henry Fane, 12th Earl of Westmorland and Lady Adelaide Ida Curzon, on 28 May 1892. She died on 21 July 1910 at age 38. She was the daughter of Robert Francis St. Clair-Erskine, 4th Earl of Rosslyn and Blanche Adeliza Fitzroy. From 28 May 1892, her married name became Fane. As a result of her marriage, Lady Sybil Mary St. Clair-Erskine was styled as Countess of Westmorland on 28 May 1892.
Children of Lady Sybil Mary St. Clair-Erskine and Lt.-Col. Anthony Mildmay Julian Fane, 13th Earl of Westmorland
Lt.-Cdr. Vere Anthony Francis St. Clair Fane, 14th Earl of Westmorland+ b. 15 Mar 1893, d. 12 May 1948
Lady Enid Victoria Rachel Fane+ b. 24 Apr 1894, d. 9 Sep 1969
Major Hon. Mountjoy John Charles Wedderburn Fane+ b. 8 Oct 1900, d. 9 Oct 1963
Lady Violet Gloria Sybil Fane1 b. 11 Apr 1902."
Her Wikipedia article is here.
From digitalhistoryproject; background fixed with Photoshop and greenish tint removed by gogm.