Please note that the schools of literary criticism and their explanations included here are by no means the only ways of distinguishing these separate areas of theory. Indeed, many critics use tools from two or more schools in their work.
Conglomerate is a clastic sedimentary rock that contains large (greater than two millimeters in diameter) rounded clasts.
Sandstone is a common clastic sedimentary rock formed by the compaction and cementation of sand (quartz grains). Conglomerate is another clastic sedimentary rock formed by the cementation of rounded boulders, cobbles, and pebbles. On the other hand, breccia forms from angular boulders, cobbles, and pebbles.