Here's a bit more on Blackbarony.
The Heraldry of the Murrays (Johnston, 1910)
Sir Alexander Murray, fourth Baronet of Blackbarony, died sp. 31st December 1741. Buried Holyrood 30th January 1742. He was M.P. for Peeblesshire 1700-02; and was served heir to his grandfather 3rd January 1710, and to his father 14th August 1733. He married at Edinburgh, 28th July 1687, Margaret, daughter of William Wallace of Helington. Having no issue, he in 1741 entailed the Blackbarony estate on his niece, Margaret, daughter of Captain Archibald (No. 338, b), and failing her issue, on the Murrays of Elibank (No. 363). He was succeeded in the title by his cousin (No. 341).
... George, sixth Lord Elibank, born 14th May 1706; died 11th November 1785. He was served heir to John Stuart of Blackbarony 3rd May 1771 (see Nos. 339 and 363). He married, 8th January 1760, Isabel Mackenzie, daughter of George, third Earl of Cromarty, who died 28th December 1801. They had two daughters. He was succeeded by his nephew (No. 363)...
... Alexander, seventh Lord Elibank, born 24th April 1747 ; died 24th September 1820. He succeeded his uncle (No. 361), and was served heir to his father 30th October 1778. On the death of John Stuart of Ascog, nephew-in-law of Sir Alexander Murray of Blackbarony, he succeeded to the Blackbarony estates under the entail executed by Sir Alexander Murray 15th January 1741 (see No. 339)...