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



Ammonites have been known to mankind for thousands of years. They are the source of numerous stories and myths. The name of this spiral-shelled cephalopod originates from the Egyptian god Ammon. Ammon was envisioned as a male 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 been known to mankind 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 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 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 durations established septa that had elaborate folds called lobes and saddles. They also established fragile lacey patterns on the outer shell. These patterns along with the shape of the shell and the structure of the septa are how this cephalopod is classified. Ammonites such as Speetoniceras from Russia are very attractive often on sale.

Considering that all living cephalopods (nautilus, octopus, and squid) are i was reading this predators, we can assume 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 by see utilizing the siphuncle. The siphuncle is a tube Full Article that connects all the chambers in the shell with the living animal. The nautilus can add or subtract gas in these chambers to control buoyancy.

Ammonite Size
Ammonites have a large range of size. Early ammonites, up until the middle Jurassic, were smaller, generally less than 9 inches or 23 centimeters.

Biostratigraphy
The difficult shell of the ammonite was quickly fossilized. This, integrated with the large abundance of this group of cephalopods and its evolutionary duration through numerous geologic durations, make it a good index fossil. Index fossils help 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 should be Triassic if you discover an ammonite from a genus understood to be from the Triassic Period. To be a great index fossil:

It must have wide distribution.

There must be a great deal of them.

It needs to come from a group that progresses quickly.

They need to be simple to acknowledge.

Ammonites satisfy all of the above criteria easily.

Extinction of The Ammonites
The end of the Cretaceous Period was also completion of the ammonites. This had to do with 65 million years earlier. Dinosaurs and lots of other types of animals and plants died out at about this same time. It is thought that a big meteor hitting earth triggered these mass terminations.

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

Ammonites of later durations established septa that had intricate folds called saddles and lobes. The difficult shell of the ammonite was easily fossilized. If you discover 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.

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