Roy's map of 1755 calls the Cauldstane Slap route the ‘Road to
Queensferry’. It is an old drove road, cattle were driven from Falkirk and
north of there, down through West Linton continuing to Peebles and St
Mary's Loch, eventually to England. It is likely that James IV travelled
this path in November of 1490 after buying a horse at Linlithgow.
In The Drove Roads of Scotland, Haldane shows it as being the only
route cattle were taken from north of the central belt south. While it is
unlikely to be the sole route, it must have been of considerably
importance and surely must have had tens of thousands of cattle
travelling across it every year. In the reverse direction, sheep from the
Linton markets were driven to the Highlands, probably about 30,000
annually.
It is also known, as many drove roads are, as the Thief's Road as it
must have been used by a fair number of cattle thieves as well as
legitimate traders. As late as 1600 there is a record of a party of Scotts
and Armstrongs stealing 80 cattle and taking them southwards along
this path, leaving several dead and wounded in their wake.