This is her article from thepeerage, "Lady Dorothy St. John F, #3635, d. 28 June 1628
Lady Dorothy St. John married John Carey, 2nd Earl of Dover, son of John Carey, 1st Earl of Dover and Judith Pelham, on 9 May 1628. She died on 28 June 1628.1 She was buried at Hunsdon, Herefordshire, England.
She was the daughter of Oliver St. John, 1st Earl of Bolingbroke and Elizabeth Paulet. From 9 May 1628, her married name became Carey."