The Ammonites (such as Speetoniceras from Russia) - (Reference|Index} Fossils



Ammonites have been known to mankind for thousands of years. They are the source of many stories and misconceptions. The name of this spiral-shelled cephalopod originates from the Egyptian god Ammon. Ammon was pictured 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
Numerous 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 thought that.

A Brief History of Ammonites
Ammonites first appeared in the Devonian Period. Ammonites of later periods established septa that had intricate folds called saddles and lobes. Ammonites such as Russian Speetoniceras are very attractive often on auction.

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

Ammonite Size
Ammonites have a wide variety of size. Specimens have actually been discovered varying from less than a centimeter to 2 meters in size. Early ammonites, till the middle Jurassic, were smaller sized, usually less than 9 inches or 23 centimeters. During the upper Jurassic and lower Cretaceous larger varieties can be found. Titanites found in the south of England can be over 50 centimeters, 2 feet in diameter.

Biostratigraphy
The difficult shell of the ammonite was easily fossilized. This, integrated with the large abundance of this group of cephalopods and its evolutionary duration through several geologic periods, make it an excellent index fossil. If you discover an ammonite from a genus known to be from the Triassic Period, then the rock layer it came from must be Triassic.

It needs to have broad distribution.

There need to be a great deal of them.

It should belong to a group that progresses quickly.

They must be simple to acknowledge.

Ammonites satisfy all the above criteria easily.

Termination of The Ammonites
The end of the Cretaceous Period was likewise the end of the ammonites. useful reference This was about 65 million years earlier. Dinosaurs and numerous other species of animals and plants died out at about this same time. It is believed that a substantial meteor hitting earth caused these mass terminations.

The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.

Ammonites of later durations established septa that had detailed folds called lobes and saddles. The tough shell of the ammonite was easily fossilized. If you discover an ammonite from a genus known to a fantastic read be from the Triassic Period, then the rock layer it came from should be Triassic. The end of the Cretaceous Period was likewise the end of the ammonites.

Leave a Reply

Your email address will not be published. Required fields are marked *