The key of reef-and rock-building role of organisms is to explain their paleoecologic characters and reef-building functions.Different reef-building organ-isms in shapes

such as massive

lamellar or tubular

branching

encrusting and indefinite shapes of vagrant or floating organisms

can construct five kinds of autochonous limestones in distinct ways:framestone

coverstone

bafflestone

bindstone and biocement stone.The same shape of reef-building organisms may have similar reef-building functions and forming mechanisms even in various geo-logical times.That is

framestones

bafflestones and some coverstones may form primary framework of reef;bindstones

biocementstones and some coverstone sgenerally construct the secondary framework of reef.