Flora of Palaeozoic coal balls of China | Semantic Scholar
WEBThe geographic distribution of coal balls of China and their stratigraphic range are very wide. Fossil plants in coal balls are abundant Floras of coal balls of Jingyuan Gansu contain the same content as those of the Hauptfloz coal of Ruhr and the Kokfloz coal of Ostrau (Namur C) in Europe. Coal balls of Shanxi and Shandong (P1) are abundant .