+---Richard Jamieson (ABT 1946-)
| | +---Richard Henry Northcott (ABT 1858-)
| | +---Richard Henry Northcott (26 JUN 1884-20 JAN 1927)
| | | +---Elizabeth Jordon 
(ABT 1855-)
| +---Audrey Northcott (29 OCT 1920-)
| | +---Nicholas Trevithick (ABT 1618-FEB 1698)
| | +---Thomas Trevithick (ABT 1664-MAR 1723)
| | | | +---Thomas Couch
| | | +---Peternell Couch (ABT 1640-DEC 1696)
| | | +---Elizabeth ?
| | +---Thomas Trevithick (ABT 1697-FEB 1771)
| | | | +---John Peters (ABT 1639-)
| | | +---Mary Peters (ABT 1665-)
| | | +---Marrian Spry (ABT 1643-)
| | +---Thomas Trevithick (ABT 1736-MAR 1804)
| | | | +---John Bennett (ABT 1680-JAN 1717)
| | | +---Mary Bennett (ABT 1706-1742)
| | | +---Pricilla ? (ABT 1680-)
| | +---John Trevithick (ABT 1778-DEC 1854)
| | | | +---John Sarel (ABT 1707-)
| | | +---Rebecca Searle (ABT 1733-MAY 1823)
| | | +---Jone Pasco (ABT 1711-)
| | +---Thomas Trevithick (ABT 1806-1887)
| | | | +---Richard Parrow (ABT 1752-MAY 1824)
| | | +---Honor Perrow (21 APR 1782-1857)
| | | +---Jane Sara ? (ABT 1749-JAN 1823)
| | +---John Trevithick (ABT 1834-07 SEP 1885)
| | | | +---Thomas Bassett (ABT 1779-)
| | | +---Susanna Bassett (ABT 1805-1891)
| | | +---Elizabeth Glanville (ABT 1783-)
| | +---William John Trevithick (07 OCT 1857-01 APR 1928)
| | | | +---William Kennedy (ABT 1805-)
| | | +---Ann Kennedy (ABT 1831-1903)
| +---Eliza Wills Trevithick (20 JAN 1885-09 AUG 1952)
| | +---George Tonkin
| | +---George Tonkin (1758-)
| | | +---Jane ?
| | +---James Prout Tonkin (ABT 1800-)
| | | +---Jennifer (Jane) Prout
| | +---William Tonkin (ABT 1831-)
| | | +---Jane Tredinnick
| +---Elizabeth (Bessie) Paull Tonkin (ABT 1862-1942)
| | +---Joseph Wills
| +---Eliza Wills (ABT 1828-)
| +---Martha ?
David Jamieson
+---Jill ?