A stunning example of a calcite ammonite fossil of the species Asteroceras obtusum from the world-famous Jurassic Coast beach of Lyme Regis, Dorset UK.
The ammonite sits inside the original piece of limestone matrix in which it was found, that has been split open to reveal both the positive and negative parts of the shell. The main piece of matrix measures 165 mm (6.5 inches) across and the fossil ammonite measures 68 mm (2.72 inches) across. The ammonite is well preserved and has been prepared out of the rock to reveal the shell. Part of the outer whorl is missing, which likely happened when the rock fell from the cliffs to the beach.
There is also an unusual bivalve shellfish in the aperture (shell opening) of the ammonite.
This is what is known as a "popped" ammonite, meaning that when the rock split, both the positive shell and cast in the matrix were revealed. The ribs are very finely defined and the mottled yellow and brown colour is beautiful. The two pieces of matrix fit back together, hiding the surprise within, and the both have cut-flat bases to allow them to be displayed free standing.
A great example of the species and impressive in the flesh. Both piece of matrix weigh 2066 grams together. These are very sought after ammonites from this world-famous location.
Around 196 million years old (Sinemurian, Early Jurassic), this fossil would make a wonderful addition to any collection.