07345 - Beautiful 1.02 Inch Chalcedonized Fossil Gastropod Cretaceous Dakhla Neltneria No fractures or restoration

No fractures or restoration

Part of the digestive system is preserved and visible

Although it has commonly been assumed that concretions grew incrementally from the inside outwards

In this matrix

The exact taxonomic classification is complex given that there are very few published studies that refer to the claw rests of the Pterosaurs in the North African Upper Cretaceous

07345 - Beautiful 1.02 Inch Chalcedonized Fossil Gastropod Cretaceous Dakhla Neltneria No fractures or restorationChaledonized gastropods (specimen at fat left is 3. 0 cm tall) these snail shells have been replaced by translucent, fibrous, microcrystalline quartz (SiO2). This variety of quarz is called chalcedony. Chalcedonization is a variety of silicification. Chalcedonized fossils are uncommon.