(-ABT 1730)
+---Richard Morlyn (-ABT 1735)
| | +---Nicholas Trethewy (-ABT 1680)
| +---Julyan Trethewy 
(ABT 1652-)
| | +---Bartholomew James (-ABT AUG 1636)
| | | +---Sicelie ? (-1608)
| +---Petronell James (-ABT 1692)
| +---Joan ?
John Morlyn (ABT 1722-17 JUL 1799)
+---Elizabeth Rogers