Thank you,Len, for your response with its interesting idea. However,I rather
doubt if there were 2 couples entangled here, because in John Kennaugh's
petition he refers to his wife Patience being one of the daughters of Matthias.
However if your idea were right she would have been the only surviving daughter
because the records show Elinor (bpt.21.10.1770) as having died in childhood.
I did wonder at one time if Jane Gellin had died after the 5th child was born,
and Matthias married Jane Cowin about 1767. However that would not explain the birth of a son to Matthias & Jane Gellin in 1776. Also I cannot find
any record of a marriage between Matthias or Matthew Quayle and Jane Cowin.
It is intriguing. Thank you so much for your interest and help.

Eleanor.