Ponce Limestone includes beds of brown clay and has a maximum estimated thickness of 850 meters.[4] 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.[5]
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.[7]
Geologia del Distrito Ponce. G. J. Mitchell. Revista de Obras Publicas de Puerto Rico. Year VII. Issue 1. January 1930. Pages 7–9. Accessed 1 August 2020.
Further reading
Monroe, W.H., 1972, Geology of the middle Tertiary rocks in the Ponce-Guanica area—a progress report: U.S. Geological Survey Open-File Report 72-258, Washington, D.C., scale 1:20,000.
Volckmann, R.P., 1984a, Geologic map of the Cabo Rojo and Parguera quadrangles, southwest Puerto Rico: U.S. Geological Survey Miscellaneous Investigations Series Map I-1557, scale 1:20,000.
Volckmann, R.P., 1984b, Geologic map of the Puerto Real quadrangle, southwest Puerto Rico: U.S. Geological Survey Miscellaneous Investigations Series Map I-1559, scale 1:20,000.