The Ammonites to Collect - (Reference|Index} Fossils



Ammonites have been understood to humanity for thousands of years. They are the source of numerous stories and misconceptions. The name of this spiral-shelled cephalopod comes from the Egyptian god Ammon. Ammon was visualized as a male with the horns of a ram extending from his head. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites. Ammonites have been known to humanity for thousands of years. The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.

Ammonite Myths
Lots of cultures throughout history have attributed special 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 excellent 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 first appeared in the Devonian Period. Ammonites of later periods developed septa that had intricate folds called lobes and saddles. Ammonites such as Speetoniceras from Russia are very attractive often on auction.

Given that all living cephalopods (octopus, nautilus, and squid) are predators, we can assume that ammonites were too. The only living cephalopod with an external shell is the chambered nautilus. It can swim and manage its depth. It does this by using the siphuncle. The siphuncle is a tube that links all the chambers in the shell with the living animal. The nautilus can deduct or include gas in these chambers to control buoyancy.

Ammonite Size
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, until the middle Jurassic, were smaller sized, typically less than 9 inches or 23 centimeters. Throughout the upper Jurassic and lower Cretaceous larger ranges can be found. Titanites discovered in the south of England can be over 50 centimeters, 2 feet in size.

Biostratigraphy
The tough shell of the ammonite was easily fossilized. This, integrated with the large abundance of this group of cephalopods and its evolutionary duration through numerous geologic periods, click to find out more make it a great index fossil. Index fossils assist paleontologists and geologists to figure out 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 originated from must be Triassic. To be an excellent index fossil:

It needs to have large distribution.

There must be a lot of them.

It needs to come from a group that progresses rapidly.

They must be easy to recognize.

Ammonites please all the above requirements quickly.

Termination of The Ammonites
The end of the Cretaceous Period was also the end of the ammonites. Dinosaurs and numerous other species of plants and animals died out at about this same time.

The curled ammonite you could try these out shells resembled the horns and were called Ammon's Stones or ammonites.

Ammonites of later periods developed septa that had complex folds called saddles and lobes. The difficult shell of the ammonite was easily fossilized. 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. The end of the Cretaceous Period was likewise the end of the ammonites.

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