I found this interesting and lively (!) account of Justice John Gaston in a book called "Carolina Backcountry on the Eve of the Revolution." It's from the diary of Charles Woodmason, an English Anglican minister trying to preach to the people of the backcountry (many of them Scotch-Irish Presbyterians who resented the Anglicans for their treatment back in Ulster). John Gaston appears to have really disliked Anglicans!
From this place I went upwards to Cane Creek where I had wrote to the Church [of England] people for to assemble - But when I cam I found that all my letters and advertisements had been intercepted. I trac'd them into the hands of one John Gaston, an Irish Presbyterian Justice of the Peace on Fishing Creek, on the other side of the River."
P. 35: "Next day the people in Fishing Creek came to wait on me and told me that they [had] expected me last Sunday agreeable to my advertisement - and that a multitude met from distant places and above 30 children brought for baptism. This surpriz'd me as I had sent up no such advertisement - so resolved to search into this Presbyterian trick.
P. 40: "I have unravelled the mystery of the advertisement set up at the Waxaws. Twas done by one John Gaston a Justice of the Peace among the Presbyterians, to have a laugh at the Church [of England] people. He has also set up to marry people, and has actually married several couple, tho' his own pastor lives but a few miles from him. There is a strict law against all this, and altho' I have got depositions against the wretch, I can find none to serve [it}.