(ABT 1517-ABT 1573)
+---Thomas Trethewy (-ABT 1616)
+---Bartholomew Trethewy
+---Bartholomew Trethewy (-1666)
+---Bartholomew Trethewy
+---Thomas Trethewy (ABT 1675-MAY 1743)
| +---Jane Bruart 
+---Thomas Trethewy (ABT 1710-FEB 1795)
| | +---Phillip Mellow (ABT 1660-JAN 1711)
| +---Joan Mellow (ABT 1680-)
| +---Jane ?
Richard Trethewy (ABT 1752-NOV 1816)
| +---Richard Jolliffe
| +---Robert Jolliffe
| +---Robert Jolliffe (ABT 1546-1602)
| +---Henry Jolliffe (ABT 1586-)
| | +---Thomason ?
| +---Francis Jolliffe (ABT 1622-)
| | +---Blanch Pearce
| +---James Jolley (ABT 1682-APR 1754)
| | +---Rose May
+---Elizabeth Jolley (ABT 1713-)
| +---Richard Osborne (-JUN 1667)
| | +---Eme Varcoe
| +---Richard Osborne
| | +---Joan ?
| +---Richard Osborne (-NOV 1707)
| | | +---Arthur Michell (-ABT 1657)
| | +---Constance Michell (ABT 1635-APR 1717)
| | | +---Thomas Corne (-1647)
| | +---Blanche Corne
+---Blanche Osborne
+---Bettres ?