Pleuroceras spinatum
Ammonita; Pleuroceratidae
Geological Time: Jurassic Lower Lias
Size (25.4 mm = 1 inch): 55 mm diameter
Fossil Site: Untersteurmig, Germany
Code: AA101
Price: Sold
 Description:
A superb example of the ammonite Pleuroceras spinatum of the Lower
Lias (200 m.y.a) deposits of Germany, this one looks more like
a bronze sculpture than the remnants of a living organism. The
environment was anoxic, leading to formation of Iron Pyrite (Fool’s
Gold). This one is essentially solid pyrite, with only the intricate
suturing pattern that gave strength to the shell for minimum weight
highlighted in a delicate white tracery. The ridge along the dorsal
edge is the remnant of the siphuncule, the means by which the ammonite “shifted
ballast” in order to rise and fall in the water column. This
most artistic specimen would make a fine addition to any ammonite
collection. |
