which trees are rooted have paleosols developed within them. Retallack (1981, 1997) has published pictures and diagrams of the Yellowstone upright fossil trees having intact root systems developed within paleosols found within these strata. Formation by regeneration Geologists have also found that some of the larger upright fossil trees found within Carboniferous coal-bearing strata show evidence of regeneration after being partially buried by sediments. In these cases, the trees were clearly alive when they were partially buried by sediments. The accumulated sediment was insufficient to kill the trees immediately because of their size. As a result, some of them developed a new set of roots from their trunks just below the new ground surface. Until they either died or were overwhelmed by the accumulating sediments, these trees would likely continue to regenerate by adding height and new roots with each increment of sediment, eventually leaving several meters of former "trunk" buried underground as sediments accumulated. Formation by Carboniferous deglacial meltwater-pulses In addition, part of the Carboniferous Period was a period of extensive and thick continental ice sheets. During the Carboniferous ice age, the repeated glacial – interglacial cycles caused major changes in the thickness and extent of continental ice sheets. When these ice sheets expanded in extent and thickness, eustatic sea level typically fell by over a . When these ice sheets shrank in extent and thickness, eustatic sea level typically rose again by typically over a . As occurred during the Holocene Epoch for Meltwater pulse 1A and Meltwater pulse 1B, brief episodes of rapid melting of Carboniferous, Gondwanan continental ice sheets likely caused very rapid rises in sea level that would have abruptly inundated low-lying coastal swamps and drowned the forests growing on them. Based on the sedimentology of roof strata of surface and underground coal mines and cyclothems containing the fossils of upright and in situ tree trunks, geologists proposed that the flooding of coastal swamp by deglacial meltwater pulses resulted in the rapid flooding of coastal forests, particularly along preexisting coastal rivers and streams, over large areas of coastal swamp. During and after their submergence, upright trunks of drowned coastal forests were buried by tidally influenced sedimentation. Association with marine fossils Geologists find nothing anomalous about upright fossil trees found in Carboniferous coal-bearing strata being associated with marine or brackish-water fossils. Because they lived on subsiding coastal plains or pull-apart basins open to the coast, it