Invertebrate Fossils OF NJ

Baculites sp. (Lamarck)

  Baculites, also known as the walking stick rock are a nearly straight-shelled type of ammonite that lived worldwide throughout the Late Cretaceous period. Like all ammonites, the shell consisted of a series of body chambers, which contained gas to kept the animal buoyant. Baculites fossils are very brittle and are almost always found broken. The breaks usually occur along the suture lines where the individual chambers were connected. Both baculites and ammonites belong to the class Cephalopoda and share many characteristics. The obvious distinction between the two is the  shape. Ammonites are coiled, while baculites are straight. Baculites are generally an uncommon find in New Jersey, although some locations may produce speciments on a more regular basis.

Baculite from Monmouth County, NJ.
1 1/2 inches across.
 

Close up of the suture line.
Differences in the suture lines can be used to help identify
the different species.
 

The cross section of Baculites are round or oval in shape.  Ammonites
would have more of triangular shape.

The internal structure of the suture on a baculite is much more pronounced
then on an ammonite.