Chert-Shale-Mudstone

Photomicrograph of a coal ballThe coal balls are early diagenetic nodules which formed beforecompaction and alteration of the organic matter. These arecomposed of calcite or dolomite and well - preserved plant material.In this Carboniferous coal ball, fragments of the large trees areabundant. This indicates that the coal was derived from peat offorest-swamp environment (From Tucker, 1996).13