Abstract
A study of Devonian faunas from North Cornwall shows that a considerable area of beds hitherto regarded as Upper Devonian are of Middle Devonian age. Goniatite localities at Trevone Bay and Portquin correlate with the Upper Maenioceras Stufe of Germany: other localities within the area mapped as Grey Slate by the Survey are also Middle Devonian. Only the area marked as Purple and Green Slate by the Survey has yielded Upper Devonian goniatites.