Locality 96-17. 69° 08' 57" N 162° 39' 41" W
Kukpowruk Formation
Specimens: 96 RAS 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 100, 101, 102, 103, 104, 105, 106
Description. Lumpy gray/brown siltstones/mudstones with decimeter scale bedding overlain by fine cross-bedded and rippled gray/brown sandstones with some small bivalves identical to those at locality 16. The mudstones are abundantly rooted with long Equisetites rhizomes and Birisia is common. Both fertile and sterile Arctopteris occurs together with Sphenopteris sp. Podozamites is rare but when it occurs the leaves are large. Ginkgo is common. Three Nilssonia species occured in close proximity in the gray/brown mudstones. Pityophyllum is absent. Arctopteris, Nilssonia, Equisetites and large leaved Ginkgo are the most common taxa at this site. The fern fronds were often minimally fragmented but many specimens were preserved not flat on bedding planes but curved or "rolled" within the poorly bedded sediment.
Interpretation. Near channel and possibly near marine overbank environment periodically, but not frequently, invaded by sediment. The flora appears to represent a later successional stage of community development than that seen in the exposure at locality 11. Sediments were extensively bioturbated by roots suggesting the vegetation was well established. Woody taxa are in a minority and no large woody remains were seen. The succession may have begun with an Equisetum/Birisia marsh but this community was subsequently invaded by a diversity of ferns, cycadophytes and ginkgoes. Salinity may have played a lesser role in determining community composition compared to the Birisia marsh of locality 11.
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