ABSTRACTRecent carbonate sediments from Jamaican north coast fringing reefs were collected along three parallel traverses in the vicinity of Discovery Bay. Each traverse extended from near shore across the back reef, reef crest, and fore reef to a depth of 75 m. Relative abundances of the biotic constituents vary between sites, reflecting general patterns of reef community composition. The sediment is dominated by highly comminuted coral fragments (27·1% to 63·1%), plates of the calcareous green algaHalimeda(0·4% to 38·7%), coralline algae (4·7% to 16·2%) and the encrusting foraminiferanHomotrema rubrum(0·7% to 9·5%), with lesser amounts of other taxonomic groups (non‐encrusting foraminifera 1·3–5·5%; molluscs 1·4–7·0%; echinoderms 0·9–5·0%). Coral fragments, coralline algae and particles ofHomotrema rubrumdominate the sediments of the shallow portions of the fore reef (5–15 m), whereas plates ofHalimedaare most abundant in sediments from the back reef and deeper portions of the fore reef ( 24 m). Q‐mode cluster analysis, using sediment constituent data, resulted in the delineation of four reef biofacies over the depth ran