Definition of "Sidlaws"

So, despite the obvious difficulties of crossing the intervening Sidlaws, correspondents to the Dundee newspapers in 1817 were advocating a "terraqueous undertaking" in the form of a canal from the town into Strathmore.

1951 August, S. G. E. Lythe, “The Dundee & Newtyle Railway: I—Promotion and Management, 1825-1846”, in Railway Magazine, pages 546-547