Lord Mark Kerr (Royal Navy officer) Wikipedia
Vice-Admiral Lord Mark Robert Kerr (12 November 1776 – 9 September 1840) was an officer of the Royal Navy, the third son of William John Kerr, 5th Marquess of Lothian by his wife Elizabeth, daughter of Chichester Fortescue of Dromisken.
Kerr served as an officer in the Lion (64) with Lord Macartney in his visit to China in 1792, and was present at the capture of Minorca in 1798. He married on 18 July 1799 Charlotte (11 February 1778 – 26 October 1835), third daughter of Randal William Macdonnell, sixth Earl, and Marquess of Antrim; she succeeded him as Countess of Antrim (creation of 1785) in her own right on the death of her elder sister. They had a large family, two of their sons succeeding as fourth and fifth Earls of Antrim.