The Ammonites to Collect - (Reference|Index} Fossils
Ammonites have been understood to mankind for thousands of years. They are the source of lots of stories and myths. The name of this spiral-shelled cephalopod originates from the Egyptian god Ammon. Ammon was imagined 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 humanity for thousands of years. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.
Lots of cultures throughout history have actually attributed special 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.
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 initially appeared in the Devonian Period. Early curled species had easy septa with a single arc like the members of the class orthocerida. Ammonites of later durations established septa that had actually complex folds called saddles and lobes. They likewise developed delicate lacey patterns on the outer shell. These patterns together with the shape of the shell and the structure of the septa are how this cephalopod is categorized. Ammonites such as Speentoniceras subinversum are highly collectible fossils often on sale.
Considering 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 control its depth. It does this by utilizing the siphuncle. The siphuncle is a tube that links all the chambers in the shell with the living animal. The nautilus can include or deduct gas in these chambers to manage buoyancy.
Ammonites have a large range of size. Specimens have been discovered ranging from less than a centimeter to 2 meters in diameter. Early ammonites, until the middle Jurassic, were smaller, typically less than 9 inches or 23 centimeters. During the upper Jurassic and lower Cretaceous larger varieties can be found. Titanites discovered in the south of England can be over 50 centimeters, 2 feet in size.
The difficult 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 durations, make it a good index fossil. Index fossils assist 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 must be Triassic if you discover an ammonite from a genus understood to be from the Triassic Period. To be a great index fossil:
It should get more have wide distribution.
There need to be a great deal of them.
It should belong to a group that evolves quickly.
They should be easy to acknowledge.
Ammonites satisfy all of the above criteria quickly.
Extinction of The Ammonites
The end of the Cretaceous Period was likewise completion of the ammonites. 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 thought that a huge meteor hitting earth triggered these mass extinctions.
The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites.
Ammonites of later durations developed septa that had actually elaborate folds called lobes and saddles. The difficult shell of the ammonite was easily fossilized. If you find an ammonite from a genus understood to be from the Triassic Period, then the rock navigate to these guys layer it came from should be Triassic. The end of the Cretaceous Period was also the end of the ammonites.