Baculites

Baculites, a genus of the family of Ammonitidæ, differing from the true Ammonites (q.v.) in the perfectly straight form of the shell, which tapers to a point, and is either round or compressed. The species, like the other Ammonitidæ, are all fossil. Baculites are characteristic of Baculite, the chalk, and appear to have existed only towards the expiry of the period over which the existence of the Ammonitidæ extended.