Merriam,-D.F.; Fuhr,-J.M.; Jenkins,-R.V.; Zimmerman,-P.J. Pleistocene bedrock geology of Florida Bay, the Keys and the Everglades. BULL.-MAR.-SCI. 1989. vol. 44, no. 1, pp. 519-520. The Late Pleistocene Miami Limestone of southern Florida comprises three facies: bryozoan, coral and oolite. The coral facies of Miami is termed the Key Largo Limestone and the oolitic facies, the Miami Oolite (= Key West Oolite). The three facies interfinger locally and all are approximately 130,000 ybp in age. The Florida Keys are an archipelago of elongate coral limestone islands, near-parallel to the present offshore reef, and extend from near Miami, Florida, southwest to Bahia Honda Key and continue under water as far west as the Dry Tortugas. Diamond-drill cores taken of the bedrock in Florida Bay reveal that the bryozoan facies underlies most of the Bay, but in a more complicated manner than previously suspected. Patch reef(s) occur locally in the Bay; one has been identified just east of East Key about 45+ feet thick. In other parts of the Bay, freshwater limestone has been observed. The bryozoan facies is composed of peletal packstones and grainstones and is so named because locally up to 70% of the rock may be composed of colonies of the bryozoan Schizoporella floridana . After bryozoans, pellets are the most abundant constituent; other important constituents are miliolids, peneroplids and ooids and locally the unit contains burrows and calcareous worm tubes.