 In detail, shelly limestone's are formed when rocks containing different minerals get weathered down then get transported to a standing body of water.From here organisms that precipitate carbon, phosphate, and silicate materials (which forms the rocks Shelly texture) combine with the minerals and go through a process called deposition, where the minerals and organic components sort by size and density.Once sorted, the fragments go through Diagenesis, where the fragments compress and cement together, and over time will form a Shelly limestone.