Kelly Limestone
The Kelly Limestone is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the Early to Middle Mississippian.
Description
The Kelly Limestone consists of approximately of marine limestone. It is found in the Lemitar, Ladron, and Magdalena Mountains of west-central New Mexico, US. The formation rests on Precambrian basement rock and is overlain by the Sandia Formation. The Kelly Limestone is divided into a lower Calosa Member and an upper Ladron Member, which are separated by an unconformity.The Kelly Limestone likely correlates with the Arroyo Penasco Group in northern New Mexico and the Leadville Limestone of Colorado. These were deposited in a major marine transgression in the Mississippian.
Fossil content
The formation contains fossil conodonts indicating that it ranges from Tournaisian to Visean in age.The lower Caloso Member contains fossils of the brachiopods Beecheria chouteauensis and Spirifer centronatus and the fusulinids Latiendothyra, Medioendothyra, and
Tuberendothyra. The upper Ladron Member contains a diverse fossil assemblage, including brachiopods such as Rhipidomella and Linoproductus, blastoid echinoderms such as Pentremites conoideus, cnidarians such as Zaphriphyllum casteri, and numerous species of microscopic algae and foraminiferans.