+---William H Gerrens
| +---Mary ? 
Joseph Henry Gerrens (ABT FEB 1876-1956)
| +---Alexander Bone
| +---Thomas Bone (ABT 1780-JAN 1844)
| | +---Rebecca Boney
| +---Charles Bone (ABT 1824-)
| | | +---William Blackmore
| | +---Frances (Fanny) Blackmore (ABT 1781-MAR 1849)
| | | +---Peter Birt
| | +---Grace Seage Burt (ABT 1755-)
| | | +---John Tregenza
| | +---Mary Tregenza (ABT 1725-)
| | +---Grace Seage
+---Ellen Bone (ABT 1852-)
+---Mary Ann Westlake (ABT 1827-)