The way the marriage record reads they were both of South Cadbury. There are two records there that may relate.
John Ryall Baptism 24 Jun 1675 South Cadbury, Somerset, parents Elias & Mary.
Elizabeth Michell Baptism16 May 1686 South Cadbury, Somerset, parents John & Ann
I cannot tie Elizabeth with a Richard. There were only 3 Richards born in the County around that period but no apparent Elizabeth, however
Richardas Mitchel (father Johannis) Baptism 12 Apr 1683 Corton Denham, Somerset may be related?
Colin