The plant assemblage represents a peat-forming phytocoenosis buried in situ by volcanic ash-fall as indicated by frequent occurrence of upright stems rooted in the underlying coal and large plant fragments occurring at the base of the tuff. It is a low-diversity herbaceous and subarborescent assemblage dominated by small ferns and calamites with subdominant lycopsids not taller than about 1–1.5 m.
This unique herbaceous assemblage comprises four fern species (Kidstonia heracleensis, Dendraena pinnatilobata, Desmopteris alethopteroides and Sphenopteris cirrhifolia), Calamites sp. and the small lycopsid Spencerites leismanii.