St. Pierre et Miquelon, 4 Jan 1768
This citation is wrong. The transcription of the register located at http://209.205.50.254/boblang/index.html clearly indicates that this is the date of marriage of Jean and Marie (FORTIN) LANGLOIS' "son" Augustin.
Jean and Marie (FORTIN) LANGLOIS are listed as the parents of Augustin LANGLOIS who married Marie DESNOYERS in 1768.