A partial tooth plate of Ctenodus cf. C. interruptus from the uppermost Hea
th Formation (Chesterian, equivalent ts Namurian E 2b), Montana, is describ
ed. This record extends the occurrence of Ctenodus to the western part of N
orth America. Ctenodus species are common in Europe and have also been reco
rded from the eastern side of North America and from Australia.