Sphenodiscus lenticularis Age: Cretaceous Formation: Fox Hills Formation Location: South Dakota Size: Ammonite is 3.2 inches across Price:SOLD
This is a very uncommon US ammonite. It is a Sphenodiscus lenticularis (second photo) from the Late Cretaceous of South Dakota. This type of ammonite is extremely lenticular in shape. The planispiral shell of the cephalopod has a very sharp keel. This distinct ammonite is well preserved, and the colorful ammolite shell is readily seen. The natural coloration of the fossil is quite striking and contrasts beautifully with the grayish-brown matrix. The ammonite is wonderfully showcased on the large, natural block of concretionary matrix that also contains other ammonites (first photo) and many other fossils. This is a fine example of this unusual ammonite from the Fox Hills Formation.
A Certificate of Authenticity from EXTINCTIONS is included with this specimen.