Juliana, daughter of William de Vescy, of Alnwick, Northumberland, and Malton, Yorks, by Agnes, daughter of William de Ferrers, 5th Earl of Derby of the 1138 creation, thus acquiring Arleston, Derbys. [Burke's Peerage]
Note: Ancestral Roots states Richard Vernon is of Harlaston, Staffordshire & Haddon. Maybe Juliana also got Harlaston.