Investigations were conducted on Grand Cayman, located some 150 miles osuth of Cuba and approximately the same distance northwest of Jamaica. Its variety of both Recent and Pleistocene carbonates provides excellent opportunity for studying a spatially coherent group of carbonate environments which can be examined in a minimum of time and travel. The sedimentary deposits of which Grand Cayman is composed are exclusively carbonates derived from a broad spectrum of environments. These sediments display an extensive array of textures, constituent particles, and diagenetic alterations which are the resultants of combined physical, chemical, and biological processes. Catastrophic events, such as storms and sea level fluctuations, help shape both Recent and Pleistocene sedimentary deposits. A systematic environment by environment evaluation of the major marine habitats is given from the quiet water areas of sounds to the high energy reef crest and across the fore-reef shelf to a maximum depth of about 100m. Emphasis is placed on organic community structure and zonation. Process-form relationships are discussed with regard to each major environmental subdivision. Maps summarize the distribution of major organic communities and bottom types around the entire island to a depth of approximately 20m are presented.