1. Maps showing sedimentary and biological environments, depth to Pleistocene bedrock, and Holocene sediment and reef thickness from Molasses Reef to Elbow Reef, Key Largo, south Florida Yale Public content 1997. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Information Services. English. Public. Florida and Key Largo Region.