AMM275 Ammonite in Matrix (South Dakota)

This ammonite specimen comes from the Fox Hills formation in South Dakota during the Cretaceous period when the area was submerged by the Western Interior Seaway millions of years ago. They are typically preserved in hard concretions that must be carefully removed. This fossil shows the ammonite naturally within its matrix, with impressions and remnants of other fossil shells like clams and other ammonites visible on the other sides. About half of the main ammonite has visible leafy suture patterns, and the ridged surface has hints of pink iridescence. Approx. 2" x 2.25" x 1.5"4.2oz (122g) Discoscaphites conradi Ammonites are prehistoric nautilus related to the modern day nautilus, squid, and octopus family. These squid-like creatures lived in the sea between 65 - 415 millions years ago. Ammonites are called cephalopods because their heads and tentacles protruded out of the same opening; they grew by building larger chambers on their shells. Some species have been found at almost 6 fee