A STRUCTURALLY DEFORMED COALIFIED TREE FROM THE LATE DEVONIAN CHATTANOOGA SHALE IN LITTLE MARROWBONE CREEK, WESTERN HIGHLAND RIM OF TENNESSEE

Unidentifiable comminuted plant detritus, Tasmanites algal spores, possible lycopods fragments, along with rare occurrences of fragmentary Archaeopteris, and Callixylon have been reported from the Chattanooga Shale in Eastern Highland Rim of Tennessee and from regions to the northeast. Plant macrofossils have not been reported in the Late Devonian Chattanooga Shale of the Western Highland Rim of Tennessee. Herein, we describe a bedding plane occurrence of structurally overprinted coalified adpressions (compression-impression) of a large (2 meters long) tree trunk or limb with associated branches from the Chattanooga Shale exposed in Little Marrowbone Creek near Ashland City, Tennessee in the Western Highland Rim. Taxonomic identification is hindered by the post-Devonian taphonomic structural overprinting of the coalified compression that obscures morphological features of the plant in the coal. The underlying shale matrix does not show impressions of plant morphology typical of adpression preservation. The coal has been sheared to producing a diagonal ridge and grove structure that resembles primary plant growth surface pattern except for its diagonal nature along the branches. The orientation of the sheared coal is coincident with primary joint orientation of 305^o in a coincident joint system with a secondary orientation of 212^o. Shale-infilled separations oriented perpendicular to the stem sides occur at semiregular intervals along the length of the trunk and resemble what would be node regions of calamataceans, but do not contain attachment scars for appendages and are devoid of coal residue. The deformation event producing the taphonomic overprint is post Late Devonian and may be related to one of the Nashville Dome foreland bulge events from the Late Paleozoic. This is the first documented occurrence large macroplants from the Late Devonian Chattanooga Shale of the Western Highland Rim of Tennessee.