New Paleontological Insights into the Emsian–eifelian Trout Valley Formation, Baxter State Park’s Scientific Forest Management Area, Aroostock County, Maine

The Trout Valley Formation of Emsian–Eifelian age in northern Maine hosts evidence of early vascular plant communities interpreted as having colonized wetland, estuarine environments. To date, collections made under permits issued by the Baxter State Park Commission, originate from outcrop along Trout Brook, its tributaries, and poorly exposed lithologies inside the woodlands. Construction of a new roadway in the Scientific Forest Management Area, oriented parallel to Trout Brook, unearthed pavement exposures in which new fossil assemblages were found. These were collected under a salvage and conservation effort. Plant megafossils, as well as new macroinvertebrates and ichnofossils, were recovered from sandy siltstone and siltstone lithofacies along a west-to-east transect along Wadleigh Mountain Road. Autochthonous plants fossils include erect axes of cf. Psilophyton forbesii and vertical rooting structures of unknown affinity. Parautochthonous and allochthonous plants include Pertica quadrifaria, Taeniocrada dubia, three species of Psilophyton, and cf. Kaulangiophyton sp., all of which are known from the area. A newly discovered shell ground of a monotypic assemblage of Modiomorpha concentrica is accompanied by trace fossils assigned to Skolithos, Planolites, and Spirophyton. The invertebrates are described to have inhabited shallow, nearshore estuarine to open marine conditions, which are unreported in the area. The co-occurrence of Modiomorpha, Spirophyton, and allochthonous axes of Pertica and Psilophyton is used as additional evidence to support a brackish water, estuarine depositional environment for the Trout Valley Formation.