Thomas is reputed to have made a fortune in what was called a Spanish voyage, no doubt to the mainland, called the Spanish Main in several parts, dying in the West Indies, S.P. With the death of Thomas the senior line ended and David became the representative of the family and his son John and his descendants continued to be head of the Lidderdales until the death, also S.P., of Thomas William in 1851 [1884?].

There seems no record, or trace, of the fortune mentioned having been inherited by a member of the family.

Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.

On the 12th February 1698, James was served heir to his father Thomas Lidderdale of Sanct Mary Isle. He married Margaret, youngest daughter of Andrew Heron of Kirouchtrie, and widow (without issue) of John M'Kie of Larg, parish of Minnigaff. By her he had issue:

    Thomas.
    - -, daughter, who married John Douglas, surgeon.

It is stated that Thomas, son of James Lidderdale of St. Mary's Isle, went to the West Indies, made a fortune, and on what was called a Spanish voyage (no doubt to the mainland called Spanish Main in several parts) he died. The estate of St. Mary's being much burdened, it was then sold to Lady Mary Hamilton.