The material comprising the rocks coal and limestone are derived from organisms. Therefore, they are classified as organic sedimentary rocks.
Clastic (or detrital): Sedimentary rock formed from particles of other sedimentary, metamorphic, or igneous rock which has been weathered, eroded, deposited, compacted and cemented. Examples of...
They are classified by origin, method of formation, mineral composition, and texture.
They are classified or their orgin is chemical, clastic, and organic, if that's what your asking. Hope it helps! :-)
MAGMA
Rock Band is breaking up: CNET Loaded
Lady Gaga on Rock Band
Explosion Rocks the IPad Factory
Walking the Line at CES 2011