III ORGANIC ROCKS (DARK COLORED)
A. Soft; spongy when wet; very lightweight when dry; forms in swampy places 1) Fine mass with coarse plant fragments; dark gray to black Peat ([13]) 2) Plant fragments small and not easily recognized; fine-grained; black to dark gray; earthy Muck B. Hard but can be scratched with a knife 1) Black; contains bands of shiny and dull material; burns well Coal ([14]) 2) Dark gray to black; does not contain shiny bands; splits into thin sheets; burns poorly or not at all Bituminous shale