goniatite

goniatite

(ˈɡəʊnɪəˌtaɪt)

n

(Palaeontology) any extinct cephalopod mollusc of the genus Goniatites and related genera, similar to ammonites: a common fossil of Devonian and Carboniferous rocks

[C19: from Greek gōnia angle, referring to the angular sutures in some species + -ite¹]