商品の詳細

In science and geology, Ammonites are an extinct group of marine mollusk cephalopods.Connection: They are closely related to modern octopuses, squids, and cuttlefish.Shell Structure: They possessed iconic, coiled spiral shells divided internally into air-filled chambers used for buoyancy control.Timeframe: They thrived in ancient oceans from 400 million years ago until they were wiped out alongside non-avian dinosaurs 66 million years ago.Fossils: Their remains are heavily used as index fossils to date rock layers. Some specimens fossilize into a rare, iridescent gemstone called ammolite.