It is the felt pad that is glued onto the metal part of the dash, for the instrument cluster to be mounted on.  It acts as an insulation and provide some vibration resistance and to prevent squeaking of the instrument cluster mounts to the body.

This particular one came off a 1992 RRC County.

It is in good shape, other than a tear on one of the sides.  It could easily be glued back together or use it as is.