The Ammonites to Collect - (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 originates from the Egyptian god Ammon. Ammon was envisioned 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 known to humanity for thousands of years. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.
Numerous cultures throughout history have actually associated unique powers to this fossil.
In ancient Greece, it was said that if you put an ammonite under your pillow it would cure sleeping disorders and bring excellent 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 initially appeared in the Devonian Period. Ammonites of later durations developed septa that had elaborate folds called saddles and lobes. Ammonites such as Speetoniceras are very desirable often on auction.
Because 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 links all the chambers in the shell with the living animal.
Ammonites have a vast array of size. Specimens have actually been found ranging from less than a centimeter to 2 meters in size. Early ammonites, until the middle Jurassic, were smaller, typically less than 9 inches or 23 centimeters. During the upper Jurassic and lower Cretaceous bigger ranges can be discovered. Titanites discovered in the south of England can be over 50 centimeters, 2 feet in size.
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 geologic durations, make it review an excellent index fossil. Index fossils assist geologists and paleontologists to identify the age of rock layers. This is called biostratigraphy. It works like this. If you discover an ammonite from a genus understood to be from the Triassic Period, then the rock layer it originated from should be Triassic. To be an excellent index fossil:
It needs to click here to read have broad distribution.
There should be a lot of them.
It must belong to a group that evolves rapidly.
They need to be simple to acknowledge.
Ammonites please all of the above criteria easily.
Extinction of The Ammonites
The end of the Cretaceous Period was likewise completion of the ammonites. This had to do with 65 million years ago. Dinosaurs and lots of other species of animals and plants passed away out at about this same time. It is thought that a substantial meteor hitting earth caused these mass extinctions.
The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.
Ammonites of later periods established septa that had elaborate folds called saddles and lobes. why not try here The hard shell of the ammonite was quickly fossilized. If you discover 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 likewise the end of the ammonites.