Ammonites have been known to mankind for thousands of years. They are the source of many stories and myths. The name of this spiral-shelled cephalopod comes from the Egyptian god Ammon. Ammon was imagined as a man 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 understood to humanity for thousands of years. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.
Many cultures throughout history have associated unique powers to this fossil.
In ancient Greece, it was said that if you put an ammonite under your pillow it would treat sleeping disorders and bring great dreams.
If you put a golden ammonite (pryritized) under your pillow you would have prophetic dreams, the Romans believed that.
A Brief History of Ammonites
Ammonites initially appeared in the Devonian Period. Ammonites of later durations developed septa that had elaborate folds called lobes and saddles. Ammonites such as Speetoniceras versicolor are great addition to a fossil collection often on auction.
Considering that all living cephalopods (nautilus, squid, and octopus) are predators, we can assume 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 vast array of size. Specimens have been discovered varying from less than a centimeter to 2 meters in size. Early ammonites, until the middle Jurassic, were smaller, normally less than 9 inches or 23 centimeters. Throughout the upper Jurassic and lower Cretaceous bigger ranges can be found. Titanites found in the south of England can be over 50 centimeters, 2 feet in diameter.
The tough shell of the ammonite was quickly fossilized. This, integrated with the large abundance of this group of cephalopods and its evolutionary period through numerous Full Report geologic durations, make it an excellent index fossil. Index fossils assist geologists and paleontologists to figure out the age of rock layers. This is called biostratigraphy. It works like this. The rock layer it came from must be Triassic if you discover an ammonite from a genus understood to be from the Triassic Period. To be an excellent index fossil:
It needs to have large circulation.
There should be a lot of them.
It needs to come from a group that develops rapidly.
They need to be simple to recognize.
Ammonites satisfy all the above criteria easily.
Termination of The Ammonites
The end of the Cretaceous Period was also completion of the ammonites. This had to do with 65 million years back. Dinosaurs and numerous other types of animals and plants died out at about this very same time. It is believed that a huge meteor hitting earth caused these mass terminations.
The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.
Ammonites of later periods established septa that had intricate folds called saddles and lobes. The hard shell of the ammonite was quickly fossilized. If you find an ammonite from a genus understood to be from the Triassic Period, then the rock layer it came from should be Triassic. The end of the Cretaceous Period was also the end of the ammonites.