A calcarenite or clastic limestone whose detrital particles are chiefly fossils, whole or fragmented. The term is most frequently used for an aggregate of large shells more or less cemented by calcite. If the rock consists of fine-sized shell debris, it is called a microcoquina. Encrinite is a microcoquina made up primarily of crinoid fragments (see illus.). Some coquinas show little evidence of any transportation by currents; articulated bivalves are preserved in entirety and the shells are not broken or abraded.