5.7" Pennsylvanian Cone-in-Cone Structure - Kentucky

Pennsylvanian Cone-in-Cone Structure - Kentucky #255698

This is a chunk of a cone-in-cone structure, collected from the Breathitt Formation of Leslie County, Kentucky. This peculiar formation is found surrounding large concretions, such as those found in fossil beds. They are formed in response to overlying pressure as cones stacked on one another, separated by thin layers of usually calcite. This specimen has clearly defined layers, giving it the look of bark or roots.

The Breathitt Formation produces both marine and land fauna and flora fossils. About 300 million years, ago this region was a river delta next to the sea. During this period of deposition, shallow seas repeatedly came in and receded, resulted in marine layers between the coal, sandstone, and plant shale layers. These marine layers primarily contain brachiopods, but trilobite fossils have been reported in locations near this site.