Cauda galliCau"da gal*li\, . [L., tail of a cock.] (Paleon.) A plume-shaped fossil, supposed to be a seaweed, characteristic of the lower Devonian rocks; as, the cauda galli grit. Cauda galli epoch (Geol.), an epoch at the begining of the Devonian age in eastern America, so named from the characteristic gritty sandstone marked with impressions of cauda galli. See the Diagram under Geology.