The Collaborative International Dictionary of English v.0.48:

Indusial \In*du"sial\, a. [See Indusium.]
   Of, pertaining to, or containing, the petrified cases of the
   larv[ae] of certain insects.
   [1913 Webster]

   Indusial limestone (Geol.), a fresh-water limestone,
      largely composed of the agglomerated cases of caddice
      worms, or larv[ae] of caddice flies (Phryganea). It is
      found in Miocene strata of Auvergne, France, and some
      other localities. Indusiate

WordNet (r) 3.0 (2006):

indusial
    adj 1: of or relating to or being an indusium