+---Henry Croggon (01 DEC 1809-1869)
| +---Ann ? 
(ABT 1781-)
Mary Caroline Croggon (ABT 1847-1879)
| +---James Trethewy (ABT 1517-ABT 1573)
| +---Richard Trethewy (BEF 1550-)
| +---Robert Trethewy (BEF 1575-DEC 1623)
| | | +---William Hawkins
| | +---Joan Hawkins (ABT 1530-)
| +---Thomas Trethewy (ABT 1596-ABT 1664)
| | +---Ann Burgess (-ABT 1637)
| +---Robert Trethewy (AFT 1642-ABT 1690)
| | | +---William Jolley
| | +---Isabel Jolley (ABT 1606-)
| +---Anthony Trethewy (ABT 1687-)
| | | +---John Scawen
| | | +---Trehane Scawen (ABT 1614-)
| | | | | +---John Trehane
| | | | +---Elizabeth Trehane
| | +---Dorothy Scawen (ABT 1653-)
| | | +---Gregory Arundell (-ABT 1653)
| | +---Dorothy Arundell
| | +---Edith Crane (-ABT 1666)
| +---William Trethewy (ABT 1719-)
| | +---Elizabeth Retallack
| +---Henry Trethewy (ABT 1752-ABT 1800)
| | +---Amy Buckingham
| +---Henry Trethewy (29 OCT 1786-25 JUL 1871)
| | | +---Hugh Hotten (ABT 1654-SEP 1733)
| | | +---Melchizedek Hotten (ABT 1698-)
| | | | | +---John Oliver (-AUG 1668)
| | | | +---Thamason Oliver (ABT 1666-)
| | | +---Hugh Hotten (-ABT 1787)
| | | | | +---Richard Polgrain
| | | | +---Grace Polgrain (ABT 1697-)
| | | | +---Thomasin ?
| | +---Grace Hotten (ABT 1756-)
| | +---Mary Gummow
+---Amy Trethewy (ABT 1815-1858)
| +---Sampson Tresawna
+---Jane Tresawna (ABT 1791-31 MAY 1875)
+---Thomasine James (ABT 1771-)