The earliest ammonites appeared during the Devonian time period about 400 million years ago, and the last ammonites vanished in the Cretaceous time period, approximately 66 million years ago, as a result of the K-T event that killed the dinosaurs. Ammonites are excellent index fossils, which means that the presence of a particular ammonites species in geologic strata helps to identify the age of the fossils found in that layer. This is because certain species of ammonites only lived during specific time periods. Ammonites are sometimes confused with similar-appearing nautilus.An ammonite can be distinguished from a nautilus by the pattern of its shell sutures, which are more complex and squiggly in the ammonite. This undulation in an ammonite's sutures also creates a ribbed look to the outer surface of its shell, while the shell of the nautilus is smooth. This particular type of ammonite is rarer to find.
This piece is from an old collection that has been in storage since the 1970s. We have a variety of ammonites available so check out our other listings! The item "Ammonite Cadoceras Fossil England 165 Million Years Old #16310 26o" is in sale since Tuesday, April 13, 2021. This item is in the category "Collectibles\Rocks, Fossils & Minerals\Fossils\Mollusks\Ammonites". The seller is "lmaest" and is located in Salem, Utah.This item can be shipped worldwide.