SUPERB HEAVILY MINERALIZED HAMMATOCERAS AMMONITE

France

JURASSIC PERIOD (TOARCIAN):  184 - 175 million years ago

With immense natural aesthetics, this is a very high grade bronze-toned brown Hammatoceras speciosum ammonite from France.  Ammonites like these are not commercially mined so their scarcity is not only due to true rarity but also to the lack of any large scale efforts compared to mass-marketed and produced ammonites from Russia, Madagascar and Morocco.  Beautiful three-dimensional FULL undistorted inflation and form with stunning, finely detailed chamber ridges preserved.  Along with all chamber ridges, you can also see perfectly preserved inner chamber detail with the oak leaf pattern design in the surface.  NO RESTORATION OR CARVING of any detail.  From an old European collection, this is a splendid and uncommonly large example of this artistically delicate species.  A large and genuine French ammonite for an unforgettable display of natural art and prehistoric beauty.

Ammonites are extinct members of the Cephalopod class.  Modern members include nautilus, squid and octopus.  They first appeared during the Silurian Period (435 million to 410 million years ago) and were abundant and widespread in the seas of the Jurassic and Cretaceous periods (175 million to 65 million years ago).  Ammonites are important index fossils—that is, they often link the rock layer in which they are found to specific geological time periods.

Ammonites varied greatly in size.  The largest known as small as 2 cm (0.75 in) in diameter.  During the Jurassic and Cretaceous periods, ammonites evolved more streamlined shells for swimming and the structure of the shell became stronger.  Different shell shapes emerged as well, such as snail-like or uncoiled.   

The shells of ammonites had hollow chambers separated by walls called septa.  A tube called the siphuncle, connected the body with the chambers allowing the animal to fill them with water or air, changing its buoyancy in order to  rise or drop in the ocean.  Only the last and largest chamber was occupied by the living animal.  

Ammonites probably lived for one to six years, with the majority living two to four years.  They fed on plankton (tiny free-floating organisms), sea lilies, and smaller orthoceras.  Although many fed off the ocean floor, others may have caught plankton while floating or swimming via jet propulsion, expelling water through a funnel-like opening to propel themselves in the opposite direction.

Because ammonites lived exclusively in marine environments, their presence also indicates the location of prehistoric seas.

SUPERBLY MINERALIZED BROWN SPECIMEN IN FULL 3D FORM WITH FINEST DETAIL OF RIDGES AND INNER CHAMBERS

7.5" across

SOLD     AMX-103     INCLUDES STAND     Actual Item - One Only

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