Fact or Myth?: Baptism for the dead was practiced deep inside the walls of St. Paul’s Basilica?

There is an email being forwarded around that claims that there is a baptismal font deep inside the Basilica of St. Paul that was used for the purposes of baptism for the dead. Here is the text of the original email: This photo was taken by Kevin Barton, grandson of Keith Barton, a Stake Patriarch, when Kevin was on his mission to Italy in 2001. These pictures were taken in Rome at St. Paul’s Cathedral which is centuries old. Kevin found a chained off area of the Cathedral, which he shouldn’t have entered but did, and discovered this old unused, I’m sure for hundreds of years, baptismal font with a mosaic inscription above it indicating it was used for baptisms for the dead.. There are probably more old Cathedrals in Italy (If they haven’t been remodeled) that still have these closed off fonts that were used centuries ago.. I wonder why they stopped ? This is truly profound and amazing.