The Collaborative International Dictionary
Indusial limestone
Indusial \In*du"sial\, a. [See Indusium.] Of, pertaining to, or containing, the petrified cases of the larv[ae] of certain insects.
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.
Wikipedia
Indusial Limestone
The Indusial Limestone is a geologic formation in France. It preserves fossils dating back to the Neogene period.