Permian Coal Forest offers a glimpse of late Paleozoic ecology.

L ittle evokes a sense of wonder about the past like moments frozen in time: the contorted bodies of Pompeii’s horrified citizens fixed in their final poses, the footprints of an ancient hominin family cemented on an African savanna, the tracks of a Jurassic predator closing in on unsuspecting prey along a muddy riverbank, or tree stumps from an ancient Carboniferous rainforest buried in place by a sudden deluge (Fig. 1). These instances provide us with poignant snapshots of deep time, and just like a photograph, they also may capture some of its dynamism. In PNAS, the work by Wang et al. (1) reconstructs the vegetation of an ∼300 million-year-old early Permianaged mire that was buried and killed by a volcanic ashfall, one of a rare but increasing number of occurrences that geologists term T deposits (2). The study represents a high-resolution view of a Permian-aged ‘Coal Forest’, so-called because it accumulated atop peat (now coal), an extinct ecosystem that persisted in tropical East Asia long after its betterknown Pennsylvanian-aged counterparts had all but dried up in Europe and North America (1). By using a quantitative analysis of plant fossils preserved in tuff above the coal seam, the work by Wang et al. (1) provides a 3D reconstruction of the mire vegetation before the eruption, from which patterns of heterogeneity and ecological gradients emerge. Such T deposits allow paleoecologists to examine the past in much the same way neoecologists appraise modern environments, and to ask questions about the conformity of observed patterns with various aspects of ecological theory.