Catalytic converter mounting mat

A catalytic converter comprising a metallic casing, a unitary, solid catalytic element disposed within said casing, and a nonwoven mat positioned between said catalytic element and said metallic casing, said nonwoven mat comprising at least 60 percent by weight shot-free, high strength magnesium aluminosilicate glass fibers, based on the total weight of said mat, said glass fibers having a diameter greater than 5 micrometers, a length greater than about 0.5 cm, and comprising in the range from about 4 to about 20 percent by weight magnesium oxide, about 12.6 to about 32 percent by weight aluminum oxide, and about 79.9 to about 55 percent by weight silicon oxide, based on the total weight of said glass fibers, wherein said weight percent of magnesium oxide, aluminum oxide, and silicon oxide is calculated on a theoretical oxide basis as MgO, Al.sub.2 O.sub.3, and SiO.sub.2, respectively.