calcigerous
/kælˈsɪdʒərəs/Definitions
1. adjective
covered with calcis or oyster shells; having a shell-shaped or calcareous structure
“The calcigerous rocks on the beach were a popular spot for fossil hunting.”
2. adjective
resembling or covered with shells, especially oyster shells
“The calcigerous surface of the ancient monument was a testament to its age.”