Reviews
This Specimen has been sold.
HERE ARE SOME OTHER SIMILAR FOSSILS FOR SALE
Large Ammonite Fossil In Septarian Nodule - Madagascar
This is a very unusual specimen, it's a large ammonite fossil preserved inside of a septarian nodule. These nodules are mined near the village of Ambondromamy in the Betsiboka Region of Madagascar, but finding complete fossils in them is unusual. This is a large, polished, septarian nodule, with an ammonite which would be about 9" wide preserved inside of it. You can see the distinctive crack patterns of the septarian particularly on the backside. The base has been cut flat so that it displays nicely on a flat surface.
Septarian nodules are concretions containing angular cavities or cracks, called "septaria" These cracks have been filled in by various minerals causing distinctive patterns. The process which creates the spetaria remains a mystery. A number of mechanisms, e.g. the dehydration of clay-rich, gel-rich, or organic-rich cores; shrinkage of the concretion's center; expansion of gases produced by the decay of organic matter; brittle fracturing or shrinkage of the concretion interior by either earthquakes or compaction; and others, have been proposed.
Septarian nodules are concretions containing angular cavities or cracks, called "septaria" These cracks have been filled in by various minerals causing distinctive patterns. The process which creates the spetaria remains a mystery. A number of mechanisms, e.g. the dehydration of clay-rich, gel-rich, or organic-rich cores; shrinkage of the concretion's center; expansion of gases produced by the decay of organic matter; brittle fracturing or shrinkage of the concretion interior by either earthquakes or compaction; and others, have been proposed.
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.
What an ammonite would have looked like while alive.
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.
What an ammonite would have looked like while alive.
SPECIES
Unknown
LOCATION
Ambondromamy, Betsiboka Region, Madagascar
SIZE
9.5" tall, 9" wide
CATEGORY
SUB CATEGORY
ITEM
#31830
We guarantee the authenticity of all of our specimens.
