These fossils, which are about 150 million years old, come from Madagascar.
Size of the fossils about 7 - 10 cm.
Perisphinctes are a genus of ammonites, which lived in the middle to late Jurassic epoch. Ammonites were cephalopods living in the sea, primitive squids. From the ammonites mostly only the shells are preserved as fossils. These have the form of a flat, rolled up spiral.