A forthcoming publication will give the results of a four-year study of the shallow-water marine deposits found along the coasts of southeastern Florida and the Bahamas. Calcareous organic skeletons and their broken parts were found to comprise about 96 per cent of the total deposit. The remaining 4 per cent consist of quartz, magnetite, mica, volcanic glass, and a few other mineral species. Chemically precipitated aragonite is discussed, as are calcareous oolites and ellipsoidal pellets, considered as of faecal origin. One hundred and fifty mechanical analyses are interpreted in relation to sorting and distributing agencies.