PERMINERALIZED AND FUSINIZED WOOD FROM THE CRETACEOUS AGUJA FORMATION NEAR TERLINGUA, TEXAS

Several fossil wood specimens were examined from the upper shale member of the Aguja Formation exposed at sites near Terlingua, Texas. This Campanian depositional environment is interpreted as a swampy, inland floodplain. It preserves a diverse terrestrial fauna and as well as fossil leaves and wood. At this cluster of sites, the wood is either permineralized or preserved as fusain. Thin sections were prepared, and specimens were examined by light and scanning electron microscopy. Wood anatomical characters were identified and used to determine taxonomic affiliations. At these sites, gymnosperms were the dominant wood type, with at least one of the fusinized specimens identified as an angiosperm with solitary vessels. Conifers include at least two types; one with characters consistent with an araucarioid-type wood with close, alternate intertracheary pitting, and the other type with uni- to biseriate and opposite intertracheary pitting with shorter rays similar to a cupressoid-podocarpoid type wood. Our results are consistent with previous woods identified from other Aguja Formation sites. The paleoecology of the fusinized remains, along with the stratigraphic and depositional setting will be reviewed in the context of other Late Cretaceous wood floras from the western interior of North America.