marvelous-ammonites

The Marvelous, Mysterious Ammonite

The prolific ammonite was an important predator in prehistoric seas. Their fossil remains can be found from Britain, to northern Africa, to Russia to Madagascar to western Canada. They’ve been extinct since the end of the Cretaceous period, the same time when the dinosaurs died out. But ammonites left behind evidence of their life on earth in their remarkably beautiful fossilized shells.

Ammonite Classification

The ammonite was a mollusk. It belongs to the same large group that contains the snail, octopus, and the clam. More specifically, the ammonite was a cephalopod. Like the squid or belemnite, they had tentacles or feet that extended out from the head. The name cephalopod literally means “head – foot”.

Their shells were mostly wound into a tight spiral which made them resemble earlier mollusks like the nautiloid and the goniatite. There were some important distinctions between these different species.

The siphuncle, a tube that was used for buoyancy, was located along the outer edge of the spiral in the true ammonite. This was different in the goniatite and the nautilus, where the siphuncle was located in the center of the winding shell.

But the most visible distinction was the thin membrane, or septa that created small chambers in the shell of the animals. In the nautiloid, a species whose origin goes all the way back to the Cambrian period, the septa were smooth curves. In the Goniatite, a species that developed in the Devonian period, these septa developed gentle indentations in the curves. By the Jurassic and Cretaceous periods, these septa were complex convolutions that created feathery patterns on the outside of the shells.

Collecting Ammonites

Ammonite shells can be an enticing feature for collectors. In some cases, the fossilization resulted in deep red, green and blue colors in the sheen of the outer covering. These ammonites found in Alberta, Canada fetch incredibly high prices for the jewelry-quality shells. The ammonites that come form Madagascar often have shimmery outer coverings that flash red and gold in sunlight.

Still other species, often the ones that come from Russia, are pyritized with silvery metal that makes them look like they are modern sculptures.

This variety makes the ammonite a fabulous collecting piece. Many ammonites are reasonably priced for the new or young collector and as the collection develops, there are so many species and color variations that a serious collector can spend a lifetime seeking out unique specimens.

I marvel at each ammonite with awe. The shape and color patterns spark my sense of wonder and curiosity about the time in which the living animal filled the seas, sending me to books and internetsearches to satisfy my wondering. There seem to be limitless species to discover.

And then there’s the math. The elegance of the inner shell pattern, an example of the Fibonacci sequence, reminds us that nature has an innate wisdom that inexplicably draws us into its rhythm and sense of peaceful order.

Ammonites: Predator and Prey

With all this discussion of beauty, it would be easy to imagine hundreds of ammonites floating gently, idyllically, in the ancient seas. But other fossils show us the drama of those seas. The predatory ammonite was also prey. How do we know? Fossil ammonite shells show mosasaur bite-marks that no-doubt ended the life for that ammonite. How amazing that the shell fell to the sand and fossilized without being devoured!

The ammonite is a beautiful reminder of the Earth’s distant past. Our ammonite fossils for sale inspire wonder, awe, and curiosity. Discovering the life of this amazing creature can take you on a journey of geology, biology and Earth’s changing geography. Or simply hold it in your hand, enjoy its beauty, and connect with the distant past.