This Specimen has been sold.
7.1" Fossil Ammonite (Placenticeras) - South Dakota
This is an ammonite (Placenticeras meeki) that was collected from the Cretaceous-aged Pierre Shale of South Dakota. You can really feel the heft of the partial pyrite replacement of this ammonite when you hold it in your hand. There is some restoration along one edge.
Comes with a display stand.
Comes with a display stand.
These 70 million year old ammonites lived when South Dakota was a shallow inland sea. They were found preserved in concretions when split open. They then had to be hand-prepared to remove the hard rock surrounding them from their shells, a very time consuming task.
About Ammonites
Ammonites were ancient marine cephalopods, similar to today's squids and octopuses, but with a defining feature: their distinctive, tightly coiled spiral shells. These shells, resembling those of modern nautiluses, served as both a protective home and a buoyancy aid, allowing ammonites to navigate the prehistoric seas with ease. First emerging around 240 million years ago in the Triassic Period, ammonites thrived for over 175 million years, adapting through numerous forms and sizes. As predatory creatures, they likely fed on smaller marine organisms, using their tentacles to capture prey. However, their long reign came to an end 65 million years ago at the close of the Cretaceous, coinciding with the mass extinction event that also eliminated the dinosaurs.
Ammonites were ancient marine cephalopods, similar to today's squids and octopuses, but with a defining feature: their distinctive, tightly coiled spiral shells. These shells, resembling those of modern nautiluses, served as both a protective home and a buoyancy aid, allowing ammonites to navigate the prehistoric seas with ease. First emerging around 240 million years ago in the Triassic Period, ammonites thrived for over 175 million years, adapting through numerous forms and sizes. As predatory creatures, they likely fed on smaller marine organisms, using their tentacles to capture prey. However, their long reign came to an end 65 million years ago at the close of the Cretaceous, coinciding with the mass extinction event that also eliminated the dinosaurs.
SPECIES
Placenticeras meeki
AGE
LOCATION
Cheyenne River, South Dakota
FORMATION
Pierre Shale
SIZE
7.1" Wide
CATEGORY
SUB CATEGORY
ITEM
#262701
We guarantee the authenticity of all of our specimens.