Sagwon Sections 3 and 4

Plant fossils at Section 3 were collected from just above Coal III where sideritic nodules in a gray silty lacustrine claystone preserve leaf, branch wood and fruit/seed fossils. Typical taxa of this Late Sagwon phase of floral evolution include Equisetum arcticum, Metasequoia occidentalis leafy shoots, rare Mesocyparis sp. Tiliaephyllum brookense, Trochodendroides ex gr. arctica, Archeampelos mullii and Dicotylophyllum sagwonicum. In addition freshwater gastropods were recovered. Taxa characteristic of the Early Sagwon floral phase such as Quereuxia and monocot stems were absent.

Section 4 exposure is poor but the plant fossils come from below Coal IV and could only be accessed by excavating the site. Section 4 also yielded fossils representative of the Late Sagwon phase of floral evolution.

Left: Sketch of sediments observed at Sagwon Section 3 drawn by Anders Ahlberg during fieldwork in 2005.