According to information taken from the International Genealogy Index (I.G.I.), Elizabeth Jewell was the first child of Mathias Jewell and Elizabeth Moyle, and was baptised on the 14th April 1766, in the Parish of Wendron, Cornwall.
A search of the I.G.I., records shows that an Elizabeth Jewell married John Higgo (sometimes shown as Higgoe) on the 5th February 1785, in the Parish of Wendron, Cornwall. According to the I.G.I., John Higgo was baptised on the 8th September 1765. His parents are listed as Ishmael and Mary Higgo.
A further search of the I.G.I, has found only 1 family of children born to John Higgo and Elizabeth, in Cornwall. Interestingly they were all baptised in the Parish of Wendron that same Parish as Elizabeth and John were married in. However they were all baptised between 1733 and 1757, long before "my" Elizabeth and John were married.
At this stage I am not sure what became of Elizabeth and John. If anyone has anymore information about them, or you feel you may be one of their descendants, please contact me at firstname.lastname@example.org