Large Ammonite on matrix -Tropaeum bowerbanki

Saratov, near Ulijanovski, Volga River, Russia.  Early Cretaceous Period: 144 - 65 mya.  This is an example of a heteromorphic ammonite-  having an open partially uncoiled shell.  Measures 16.5" x 14".

Spiny Heteromorph Ammonite on matrix - Crioceratites spinosus

Village of Pali Lula, NW Bulgaria.  Early Cretaceous Period: 136.4 mya.  Ammonite is 2" across.  Extremely rare species found only in Bulgaria, of which only five are known. The remainder of these rare priceless ammonites reside in the National Museum of Bulgaria.

Ammonite on sculpted,  decorative matrix - Asteroceras sp.

Dorset, England.  Jurassic Period: 206 - 144 mya.  Ammonite measures 8" tall

Pachydiscus Ammonite

Chalk mine, Hover (Hannover), Germany.  Upper cretaceous Period: 83.5 - 71.3 mya.  Measures 15" wide x 11" high.