There are three bands with the name Black Mass: 1. The Frederick, Maryland based Black Mass Formed in 1987. They play Black/Death metal with guttural vocals. They have so far released: Demos, Splits and EP's:
Of Death demo - 1987
Death Will Reign - demo 1992
Dais of Blood demo - 1997
Experiments in Pain demo - 1997
Cut Your Heart Out for Satan EP - 2001
Hymns for the Sabbat demo - 2004
Alliance of Evil Split w/ Hellraised - 2004
Defiling the Masses Split w/ Defile - 2007

Read more about Black Mass on Last.fm.