Two types of root casts attached to in situ stump casts of early trees from the Catskill Delta Complex are described and contrasted. The first type is attached to bulbous sandstone tree-stump casts (Eospermatoperis sp.?) occurring in a low-chroma (gray-green), pyritic, gley siltstone paleosol of Middle Devonian (Givetian) age that is interpreted as waterlogged; this paleosol formed in a coastal-margin setting characterized by a shallow water-table. Root casts in the Middle Devonian. paleosol are horizontal to subhorizontal, strap-like (measuring 0.5-2 cm in width and up to meters long), and radiate outward fi om stump casts with distinctly flared bases. Root casts with a similar morphology also occur attached to the upper portions of stump casts, and comprised an aerial root mantle. The second type of root cast is attached to weakly flared to corm-like sandstone tree-stump casts of probable progymnosperms (Archaeopteris sp.?) occurring in a moderate-chroma (red), oxidized sandy paleosol of Late Devonian (Famennian) age that is interpreted as well-drained; this paleosol formed proximal to active alluvial channels. Root casts are dominantly vertical, taproot-lib (measuring up to 10-15 cm in diameter and up to 1.5 m long), and descend downward from the bases of stump casts with approximately a 60 degrees angle of attachment. The two types of tree-root casts differ due to development under different soil-drainage conditions. Preservation of in situ Devonian tree-stump casts and attached root casts involved degradation of interior tissues, followed by sediment infilling; outer tissue (periderm) persisted longer before decay and infilling. Preservation is favored by conditions of rapid sediment accumulation, generally associated with sandstone deposition, as is the case for Carboniferous lycopod tree stumps documented by other workers. Lack of preservation in fine-grained claystone paleosols associated with either coastal-margin mudflat or alluvial floodplain deposition reflects either (I) no colonization of these soil environments by mature trees, (2) selective destruction of the root traces by intensive physical mixing associated with vertic (shrink-swell) soil processes in clay paleosols, or (3) average sediment accumulation rates that were too low to bury and preserve in situ stump casts.
