I didn't mean to give the impression that a marker for Isaac Coats couldn't be found at Marietta. It's just that some burial information is incomplete or entirely missing. For an example of the kind of information taken available in the book, see this post on Mississippi burials at Marietta --
http://history-sites.com/cgi-bin/bbs53x/gacwmb/webbbs_config.pl?noframes;read=7865