undifferentiated rock units

Paleontology and geology

Permian rocks in the northwestern part of the state are composed of deep oceanic red chert and shale rich in siliceous plankton. Scattered reefs are found in the northeast and north central parts of the state; however, sea level was lower in the Permian and parts of the state were above sea level. Evidence of shallow lagoons and beaches can be found in the eastern part of the state, and some of the rocks contain evidence of marine invertebrates such as brachiopods, as well as plant fossils.