I am sorry that I missed your message. Work has been a little difficult recently so family research has been on the back burner. Firstly, what little research I have done in this area shows that the popular alternative spellings for your name are Comaish, Camaish, Camish and Comish. Even Cornish might be an option.
Secondly, I am researching the family of Stephen Comaish & Isabel McNamur (aka McNameer) who married in 1802. As far as I know, they had six children of whom one, Isabella, married my 3GGF, James Boyde, in 1832. Another son, James, married Esther Gawne and emigrated to Australia c1841 and had five children.
Stephen Comaish is my 4GGF, and I reckon that means that he died a long time before your GGF was on the scene. However, you could tell us what you know and we will see if we can point you in the right direction.