Fossils make up about 90% of sediment including worm tubes, pelecypods, gastropods, bryozoans, shell fragments.. Sand-sized mineral grains and rock fragments account for the remaining 10% including rounded quartz grains..
Cite the IMLGS database as: Curators of Marine and Lacustrine Geological Samples Consortium. The Index to Marine and Lacustrine Geological Samples (IMLGS). National Geophysical Data Center, NOAA. doi:10.7289/V5H41PB8 [date of access].