Ó Tuatal
Ó TUATAL—I—O Thuathayll, Tuthill, Tothill, Tuttell, Turtle, &c.; a variant of Ó Tuathail, which see. Compare with Ó Tuataigh for Ó Tuathaigh. I give this form on the authority of O'Mahony (Keating's History), but I have not been able to verify it. Tuthill is apparently an English surname.
Alphabetical Index to Irish Surnames