The Collaborative International Dictionary of English v.0.48:

Goniatite \Go"ni*a*tite\, n. [Gr. ? angle.] (Paleon.)
   One of an extinct genus of fossil cephalopods, allied to the
   Ammonites. The earliest forms are found in the Devonian
   formation, the latest, in the Triassic.
   [1913 Webster]