ABSTRACT
Introduction The seaward coasts of all the keys, from Soldier Key on Biscayne Bay south to Garden Key in the Dry Tortugas, are edged with narrow platforms of exposed, unvegetated carbonate rocks (Figure 3.1). From Soldier Key to Bahia Honda Key, these rock platforms are composed of outcrops of the Key Largo Formation and are made up entirely of weathered and recrystallized heads of massive fossil corals. These exposed fossil reefs are the remnants of the extensive late Pleistocene coralline systems that underlie the Upper and Middle Florida Keys (discussed in Chapter 1). From Scout Key (formerly West Summerland Key) and Big Pine Key westward to Key West and Boca Grande Key, these exposed rock platforms are composed of outcrops of the Miami Formation and are made up of oölitic limestone, also of late Pleistocene age (see Chapter 1). These eroded limestone outcrops, with their microkarstic surfaces, were aptly described by Rachel Carson when she pointed out, “On some of the Keys the rock is smoothly weathered, with flattened surfaces and rounded contours, but on many others the erosive action of the sea has produced a rough and deeply pitted surface, reflecting the solvent action of centuries of waves and driven salt spray. It is almost like a stormy sea frozen into solidity” (1955, p. 206).
