The Collaborative International Dictionary of English v.0.48:

Corneocalcareous \Cor"ne*o*cal*ca"re*ous\
   (k?rn?-?-k?l-k?"r?-?s), a.
   [1913 Webster]
   1. (Zool.) Formed of a mixture of horny and calcareous
      materials, as some shells and corals.
      [1913 Webster]

   2. Horny on one side and calcareous on the other.
      [1913 Webster]