The Ammonites for Fossil Collection - (Reference|Index} Fossils



Ammonites have been known to humanity for countless 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 pictured as a man with the horns of a ram protruding from his head. The curled ammonite shells looked like 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.

Ammonite Myths
Many cultures throughout history have associated unique powers to this fossil.

In ancient Greece, it was stated that if you put an ammonite under your pillow it would treat insomnia and bring good dreams.

The Romans believed 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. Ammonites of later durations established septa that had detailed folds called saddles and lobes. Ammonites such as Speetoniceras versicolor are great showcase to a fossil collection often on sale.

Given that all living cephalopods (squid, nautilus, and octopus) 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.

Ammonite Size
Ammonites have a vast array of size. Specimens have actually been found ranging from less than a centimeter to 2 meters in diameter. Early ammonites, up until the middle Jurassic, were smaller sized, typically less than 9 inches or 23 centimeters. Find Out More Throughout the upper Jurassic and lower Cretaceous bigger varieties can be found. Titanites found in the south of England can be over 50 centimeters, 2 feet in diameter.

Biostratigraphy
The hard shell of the ammonite was easily fossilized. This, combined with the sheer abundance of this group of cephalopods and its evolutionary duration through several geologic periods, make it a good index fossil. Index fossils help paleontologists and geologists to identify the age of rock layers. This is called biostratigraphy. It works like this. If you find an ammonite from a genus known to be from the Triassic Period, then the rock layer it came from must be Triassic. To be an excellent index fossil:

It must have wide circulation.

There need to be a lot of them.

It must come from a group that progresses quickly.

They must be easy to acknowledge.

Ammonites satisfy all of the above requirements quickly.

Extinction of The Ammonites
The end of the Cretaceous Period was also the end of the ammonites. Dinosaurs and many other types of plants and animals passed away out at about this exact same time.

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 must be Triassic. The end of the Cretaceous Period was also the end of the ammonites.

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