SEDIMENTARY ROCKS/Limestones 111 Figure Cross sections to illustrate the correlation between depositional environments and carbonate rock types (grains and textures) for a rimmed carbonate platform (top) and a carbonate ramp (bottom) Reproduced with permission from Spring D and Hansen OP (1998) The influence of platform morphology and sea level on a carbonate sequence: the Harash Formation, Eastern Sirte Basin, Libya In: McGregor DS, Moody RTJ, and Clark Lowes DD (eds.) Special Publication of the Geological Society of London 132, pp 335 353 London: Geological Society of London bryozoa, algae, and many other sedentary biota In turbulent conditions, shoals of oolitic and skeletal grainstone may form, as seen in the modern carbonate banks of the Bahamas, as described in more detail in (see Sedimentary Environments: Carbonate Shorelines and Shelves) In sheltered lagoons behind the high-energy environments of reefs and shoals, burrowing marine animals may excrete faecal pellets