I found a bunch of orphaned profiles that appear to be siblings. I adopted one of them so I could find them later. The biographies of each of them list the fact that they are siblings, but the parent's names are not shown. They appear to have been created by a botched GEDCOM import.
The profiles list a marriage date for the unknown parents as 10 sep 1785 in Dighton, Massachusetts. How can I find out the names of their parents with only that information?
Edit: I realize now that only some of them show that information. Half of them do not, but they've been linked to the ones who do.