shelly

adjective3

1. •
   Composed of the shells of dead marine creatures
2. •
   Abounding with shells.

   • the snail, whose tender horns being hit Shrinks backward in his shelly cave. — 1593
3. •
   Resembling, or comprising, the shell of a mollusc

   • Shrined are your offspring in a chrystal cradle, / Brighter than Helen's ere she yet had burst / Her shelly prison. — 1818