Fossilised Goniatite Ammonite


A finely preserved Ammonite fossil. This piece has been polished and cut very neatly revealing its inner chambers, where the fossil displays polychromatic crystal formations. Its v-shape of the walls between its chambers distinguishes it as a Goniatid, which is part of the Ammonoid subsection of the Cephalopod family.

Goniatite Ammonites first appeared around 390 million years ago, in the Mid Devonian period, and became extinct around 250 million years ago, in the late Permian Period. This during the Permian-Triassic extinction, which is thought to have been caused by Ocean acidification. Other species of ammonite survived this extinction.

Date: Between 390 and 250 million years old
Period: Middle Devonian - Late Permian period
Provenance: From a Surrey gentleman's collection (DG), purchased on the London Art Market from an ADA member, formed 1990's onward.
Condition: Excellent condition - fossil has been polished and cut in half to reveal its inner chambers.


SKU: AF-12 Category: Tags: , ,

Ammonites are part of the cephalopod family, along with Nautiloids (shell dwelling creatures) and Coleoids (shell-less mollusks, like squid and octopuses). Although Ammonites look similar to Nautiloids, both species inhabit a coiled shell, they are actually believed to be more closely related to Coleoids. Ammonites were born with one tiny shell and built new chambers as they grew – thereby creating the segmented shell that can be seen here. They would have moved into the new chamber, sealing off the older, smaller chambers – these older chambers were also filled with gas, allowing the ammonite to control its buoyancy.

Ammonites first appeared around 450 million years ago, during the Paleozoic Era, and became extinct around 66 million years ago, at the end of the Cretaceous period. The last ammonites became extinct at the same time as the dinosaurs, in a mass extinction called the Cretaceous-Paleogene extinction, which is believed to have been caused by an asteroid colliding into Earth.

Weight 338 g
Dimensions L 12.1 x W 9.8 x H 1.4 cm
Time Period