The fossil flora and age of the Wamsutta Formation red beds (Middle Pennsylvanian), Narragansett Basin, southeastern Massachusetts, USA and correlation with the Cumberland Group of the Maritime Provinces of Canada

摘要

New collections of plant macrofossils provide a precise Middle Pennsylvanian age for the lower Wamsutta Formation red beds of the Narragansett Basin, southeastern Massachusetts, USA. The Wamsutta assemblage indicates strong correlation with the Cumberland Group of the Maritime Provinces of Canada, which was earlier considered to be of late Langsettian to early Duckmantian age. This correlation is supported by the presence in the Wamsutta Formation of the following plant-fossil species: Neuralethopteris schlehanii, Neuropteris obliqua, Senftenbergia plumosa, Calamites suckowii, Annularia asteris, Annularia cf. microphylla, Asterophyllites charaeformis, Asterophyllites grandis, Asterophyllites lindleyanus, Sphenophyllum cuneifolium, and Sphenopteris valida. Moreover, the new fossil flora resembles the Middle Pennsylvanian florules of western Europe, such as the Laveineopteris loshii Subzone. The new flora is especially similar to those of the Iberian Peninsula, where there is a complete succession of Carboniferous macrofloral zones, and this similarity confirms a late Langsettian or early Duckmantian age for the lower Wamsutta macro flora. The new collections of Wamsutta Formation plant fossils, along with a smaller existing collection, represent the oldest known macroflora in the Narragansett Basin.