Ammonites have been understood to mankind for countless years. They are the source of many stories and misconceptions. The name of this spiral-shelled cephalopod comes from the Egyptian god Ammon. Ammon was pictured as a guy with the horns of a ram protruding from his head. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites. Ammonites have actually been known to mankind for thousands of years. The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.
Many cultures throughout history have actually attributed unique powers to this fossil.
In ancient Greece, it was said that if you put an ammonite under your pillow it would cure sleeping disorders and bring good dreams.
The Romans thought that if you put a golden ammonite (pryritized) under your pillow you would have prophetic dreams.
A Brief History of Ammonites
Ammonites first appeared in the Devonian Period. Early curled species had basic septa with a single arc like the members of the class orthocerida. Ammonites of later periods established septa that had detailed folds called saddles and lobes. They also established fragile lacey patterns on the external shell. These patterns in addition to the shape of the shell and the structure of the septa are how this cephalopod is categorized. Ammonites such as Speetoniceras versicolor are very beautiful often on auction.
Since all living cephalopods (octopus, squid, and nautilus) are predators, we can presume that ammonites were. The only living cephalopod with an external shell is the chambered nautilus. The siphuncle is a tube that connects all the chambers in the shell with the living animal.
Ammonites have a wide range of size. Specimens have actually been discovered ranging from less than a centimeter to 2 meters in size. Early ammonites, up until the middle Jurassic, were smaller, usually less than 9 inches or 23 centimeters. Throughout the upper Jurassic and lower Cretaceous bigger varieties can be discovered. Titanites found in the south of England can be over 50 centimeters, 2 feet in diameter.
The difficult shell of the ammonite was quickly fossilized. This, combined with the sheer abundance of this group of cephalopods and its evolutionary period through a number of geologic durations, make it a good index fossil. If you discover an ammonite from a genus understood to be from the Triassic Period, then the rock layer it came from should be Triassic.
It needs to have wide distribution.
There must be a lot of them.
It must come from a group that evolves quickly.
They need to be easy to acknowledge.
Ammonites please read review all of the above requirements quickly.
Extinction of The Ammonites
Completion of the Cretaceous Period was likewise the end of the ammonites. This was about 65 million years earlier. Dinosaurs and many other species of animals and plants died out at about this same time. It is thought that a substantial meteor hitting earth caused these mass extinctions.
The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.
Ammonites of later durations established septa that had complex folds called saddles and lobes. The tough shell of the ammonite was easily fossilized. If you find an ammonite from a genus understood to be from the Triassic Period, then the rock layer it came from need to be Triassic. The end of the Cretaceous Period was likewise the end of the ammonites.