Ralston in Renfrewshire
Although the name Ralston developed as a placename just to the east of Paisley in Renfrewshire during the late 13th century, there is no evidence of family succession until about two hundred years later.
Check the Wikipedia entry for Ralston.
The known line is described in sources such as Burke's landed gentry, The Scottish nation (1863) and James Paterson's History of the county of Ayr (1847) which projects one lineage. Some of the details conflict with other sources.
In general terms the first of the 'line' was John Ralston (d.1452), a priest who later became Lord High Treasurer in Scotland and Bishop of Dunkeld.
Detail from an 18th century map showing the lands of Ralston (Barshaw, Oldhall, Byres, Honeybog). The trees above Whitehaugh were known as Ralston Wood. Near the bottom is Auchentorly, a property associated with William Ralston (d.c.1753) who lived in Seedhills at the bend of the river south of Paisley.
Timothy Pont's 1590s map of Renfrewshire