Ponce Limestone

The Ponce Limestone is a geologic formation in Puerto Rico. It preserves fossils dating back to the Neogene period (20.45 million years ago (Mya).

Description
Ponce Limestone includes beds of brown clay and has a maximum estimated thickness of 850 meters. It consists mostly of yellowish-orange, soft to moderately hard, fossiliferous limestone and appears almost continuously as a narrow band extending from Bahía Montalva in Patillas to Río Pastillo, in Barrio Canas.

Deposits
Exposed in the Ponce, Río Descalabrado, Punta Cucharas, Yauco, Punta Verraco, Guanica, La Parguera, San German, and Cabo Rojo quadrangles of the United States Geological Survey maps.

Fossil content
Various fossils have been found in the Ponce Limestone: molds of gastropods, pelecypods, coral heads, and large foraminifera are indicative of deposition in shallow-water lagoon and back-reef environments. The large foraminifera, Lepidocyclina undosa and the ahermatypic “deep sea” coral Flabellum are reported within the Ponce Limestone.