Thomas Yelland (ABT 1737-)
| +---James Trethewy (ABT 1517-ABT 1573)
| +---Thomas Trethewy (-ABT 1616)
| +---Bartholomew Trethewy
| +---Bartholomew Trethewy (-1666)
| +---Bartholomew Trethewy
| +---Thomas Trethewy (ABT 1675-MAY 1743)
| | +---Jane Bruart 
+---Elizabeth Trethewy (ABT 1713-APR 1745)
| +---Phillip Mellow (ABT 1660-JAN 1711)
+---Joan Mellow (ABT 1680-)
+---Jane ?