Category:Delthyris

Del*thy"ris, n. Etym: [NL., fr. Gr. de`lta the name of the letter thy`ra door.] (Zoöl.)

Defn: A name formerly given to certain Silurian brachiopod shells of the genus Spirifer. Delthyris limestone (Geol.), one of the divisions of the Upper Silurian rocks in New York.