I've just come across this "place" also with a relative who died in 1729 (though she was born in VA). She was a Muse, not a Cass. I thought maybe there may have been a religious reason for traveling there, but can find no sign of a relic or saint or anything in the area. Have not gone past her so also possible there was a relative, but majority of relatives in VA are from England, so not likely.
I suspect it may be a variation of the number of deaths in "Y, Somme Picardie France" - http://boards.ancestry.com/localities.weurope.france.picardi...
of which I also had many. Perhaps people were typing in "Place" and instead up came "Placé, Mayenne...." (and if you type "Place, M" in location of death, "Placé, Mayenne..." is the only thing to appear.