Thanks for this Diddy.  I wasn't 100% that they died in Auchtermuchty...was going for there because their son George was born and died there (1781 -1861).  The age of Robert Petrie ties in with what I have.  I'll look into Christian Scott/Hall...
Update:  
Think these are two different Robert Petries.  Also checked out George again, and my mistake, but he was born in Collessie and died in Auchtermuchty.
The marriage I have for George's parents are Robt. Petrie and Christian Scott  1764 Collessie; names confirmed on George's death extract.
Found a marriage for a Robt. Petrie and Christian Halley 1787, Dysart, and have just discovered Robert Sr had a son, Robert, born 1763 in Collessie.  So perhaps the entry you have for Christian Petrie alias Hall is wife of Robert Jr?  
