A New genus of silicified conifer wood from the Late Triassic of Connecticut

Abstract

We report on a new genus and species of silicified wood from a locality in the Town of Southbury, Connecticut, on the southwestern margin of the Pomperaug basin, a western outlier of the Hartford basin. Although the material occurs as float, there is strong evidence that it was derived from the immediate vicinity out of the underlying South Britain Formation of Late Triassic (Norian Age). Even though silicified wood is otherwise unknown from the Early Mesozoic of New England, this locality has produced many specimens on a continuing basis since its discovery in 1828. The holotype specimen is a well preserved partial-section of a silicified trunk with an original diameter of approximately 36 cm. The wood is pycnoxylic and consists of tracheids with mostly uniseriate to occasionally alternate-biseriate, mixed (protopinaceous) pits and uniseriate rays ranging from 1 to 11 cells high. The rays consist entirely of parenchyma, have thin walls, are frequently filled with dark material inferred to represent resin, and have a single cupressoid pit where they cross a tracheid. The characters of this wood place it closest to the Mesozoic genus Brachyoxylon, of the extinct Family Cheirolepidiaceae, from which it differs only in its cupressoid cross-field pitting and the inferred resinous infilling of its ray cells. Finally, the close proximity and physical properties of a specimen of silicified wood found at Cedarhurst, Connecticut, argue for its derivation from Southbury, rather than from a blanket of Cretaceous sediment stripped during the Wisconsin Glacial Episode.