This is an interesting story the story of the Mass Grave at Duffy’s Cut. As I recall an Irish production company made a film about this a few years ago. UPDATE: Yup it was Tile Films and there’s a video too.
In the summer of 1832 a group of 57 Irish immigrants came to the area west of Philadelphia to work on the construction of the railway line. Within six weeks the men, mainly from Donegal, Tyrone and Derry, were all dead and anonymously buried in a mass grave outside the town of Malvern.
For some time it was thought that the mass grave was due to an outbreak of a dangerous disease such as cholera and this was simply a way of dealing with infection. However, the new evidence paints a different picture. While the two skulls found more recently show signs of violence and a bullet hole the previous skulls unearthed also showed trauma.
UPDATE: There’s a video of the Documentary: