(02 DEC 1907-09 JAN 1967)
Beryl Gay 
(18 DEC 1935-)
| +---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
| +---William Trethewy (ABT 1712-JAN 1777)
| | | +---Phillip Mellow (ABT 1660-JAN 1711)
| | +---Joan Mellow (ABT 1680-)
| | +---Jane ?
| +---John Trethewy (ABT 1741-)
| | +---Grace Rickard
| +---John Trethewy (ABT 1776-)
| | | +---Francis Honey
| | +---Elizabeth Honey (ABT 1742-)
| | +---Ann Johns
| +---Thomas Trethewy (ABT 1805-1884)
| | | +---William Gummow
| | +---Mary Gummow (ABT 1776-)
| | +---Mary Colman
| +---John Trethewey (ABT 1849-06 MAR 1924)
| | | +---Robert Tippett
| | +---Ann Tippett (ABT 1816-BEF 1871)
| | +---Ann Solomon
| +---Frederick Trethewy (29 DEC 1880-27 FEB 1943)
| | +---Eliza Keast (ABT 1851-29 MAR 1921)
+---Elsie Jane Trethewy (22 APR 1912-)
+---Jane Waters (22 SEP 1882-06 APR 1947)