The fossil ammonite is the classic fossil-what the man in the street thinks of when asked what fossil looks like. ammonites lived in the seas for about 140 million years, becoming extinct approximately 65 million years ago, about the same time as the dinosaurs at the end of the Cretaceous period. They first appeared during the Carboniferous period approximately 208,000,000 years ago becoming very abundant in the prehistoric seas. Ammonites belong to the group of creatures known as cephalopods, a group of creatures that today includes the ammonites closest living relatives such as the cuttlefish, octopus and squid. The only living creature that gives us a close approximation to the ammonite is the Nautilus which has very similar spiral shell structure.
The majority of ammonites have the characteristic coiled shell that is internally split into a number of small chambers. The ammonite itself lived in one of these chambers and when it grew too large for its current living chamber it formed a new one adjacent to the existing living chamber and then moved into it. This constant adding of chambers gives rise to the characteristic spiral shape of ammonites. The empty chambers were filled with gas and use to provide buoyancy in the ocean. Ammonites range in size from the quite small to the very large with large specimens commonly having shells of a metre across and weighing perhaps 100 kg. The very largest ammonites had shells with a diameter of 2.2 m.
The great thing about ammonites is as they were so prolific in the prehistoric oceans there are many many ammonite fossils to be found now. Indeed a short walk along the foreshore at Charmouth last summer produced severa,l much to my son's delight! They can also be easily found on the beaches to the west of Lyme Regis. A properly prepared ammonite can be a thing of beauty - have a look at the range shown below to see what is currently available:
![]() |
|
SVF Silver Madagascan Ammonite Iridescent 72 cm US $7.33
|
Fossil ammonite Cadoceras sublaeve US $102.75
|
|
Fossil ammonite Ludwigia sp US $12.63
|
Fossil ammonite Psuedocenoceras US $12.63
|
|
Fossil ammonite Sphaeroceras brongniarti US $39.50
|
Fossil ammonite Liparoceras cheltiense US $15.79
|
Related fossils for sale posts:
- What are fossils? Fossils are the preserved remains or traces of animals and...
- Trilobite Fossils For Sale After the ammonite, trilobites must be most commonly known and...

US $7.33