Under the Shell: An Inside View of an Ammonite Fossil
Photo credit: Frances Goodman
Bisecting and polishing an ammonite specimen allows researchers to get an in-depth view of an ammonite’s anatomy.
The largest chamber at the end of the spiral, known as the body chamber, is where the ammonite itself would have lived. The other, smaller chambers are called camerae.
In life, the ammonite would have filled these with gas or water as necessary to control buoyancy. After the death of the ammonite, the chambers may sometimes fill with crystals during fossilization, creating beautiful miniature geodes.