+---James Trethewy +---Richard Trethewy (ABT 1665-JAN 1741) +---William Trethewy (ABT 1694-) | +---Ann Martyn (ABT 1666-JUN 1738) +---James Trethewy (ABT 1719-) | +---Jenefer Sweet (-SEP 1733) +---William Trethewy (ABT 1753-) | +---Grace Warne +---Richard Trethewy (02 FEB 1799-24 DEC 1875) | +---Catherine Scholier +---John Trethewy (25 JUL 1823-24 SEP 1876) | +---Catherine Hooper (25 MAR 1796-06 DEC 1893) +---Scholyer N Trethewy (1864-1938) | +---Margaret Eleanor Ross +---Charles Roderick Ross Trethewy (27 NOV 1910-) | | +---James Trethewy | | +---Richard Trethewy (ABT 1665-JAN 1741) | | +---William Trethewy (ABT 1694-) | | | +---Ann Martyn (ABT 1666-JUN 1738) | | +---James Trethewy (ABT 1719-) | | | +---Jenefer Sweet (-SEP 1733) | | +---William Trethewy (ABT 1753-) | | | +---Grace Warne | | +---John Trethewy (25 DEC 1805-1871) | | | +---Catherine Scholier | | +---John Neal Trethewy (26 AUG 1840-03 SEP 1878) | | | +---Margaret Grinton (24 APR 1810-1860) | +---Ida C Trethewy (24 MAR 1872-OCT 1963) | +---Catherine Lohness (12 SEP 1844-14 JAN 1898) Earl Alexander Trethewy (21 JUL 1958-) | +---James Trethewy | +---Richard Trethewy (ABT 1665-JAN 1741) | +---William Trethewy (ABT 1694-) | | +---Ann Martyn (ABT 1666-JUN 1738) | +---James Trethewy (ABT 1719-) | | +---Jenefer Sweet (-SEP 1733) | +---William Trethewy (ABT 1753-) | | +---Grace Warne | +---Richard Trethewy (02 FEB 1799-24 DEC 1875) | | +---Catherine Scholier | +---John Trethewy (25 JUL 1823-24 SEP 1876) | | +---Catherine Hooper (25 MAR 1796-06 DEC 1893) | +---Austin Trethewy (-03 JAN 1924) | | +---Margaret Eleanor Ross | +---Ralph Sumner Trethewy (24 MAY 1889-01 FEB 1922) | | +---Catherine Lohness (12 SEP 1844-14 JAN 1898) +---Sylvia Emma Trethewy (09 AUG 1921-) +---Hattie Elizabeth Herman (27 APR 1898-15 DEC 1986)