How does our fossil garden grow?

Deborah Painter (USA) Plant fossils come in a wider variety than this author used to believe. This article will discuss some of the different ways that plant fossils are preserved. Casts The fossil in Figs. 1 and 2 is a cast of Stigmaria. It is comprised of greyish sandstone. Sandy sediments initially filled the empty space left by the decaying plant; in this case, a root decayed and was replaced by shale that did not preserve the cell structure. Stigmaria is a form genera name for the roots of Carboniferous lycopod trees. Form genera are genera defined for a part of an organism or plant rather than for the entire plant, in all its different parts (leaves, roots, trunk, spores and so on). The Stigmaria is a root and it may be the root of Sigillaria or Lepidodendron. Fig. 1. This is a cast of a root of one of the lycopod trees of the Lower Carboniferous, either Lepidodendron or Sigillaria. (Credits: Deborah Painter.) Fig. 2. The cast in Fig. 1 does not preserve cellular details because the cavity in the sediment left by the decaying root was filled by sediment that did not replace the original structure. (Credits: Deborah Painter.) The fossil dates from the Mississippian period (Upper Carboniferous) and is part of the Price Formation. The Price Formation is sandstone, conglomerate, quartzarenite, limestone, coal, and shale. The sandstone is feldspathic and slightly micaceous, with a few greyish red beds. The Price Formation is a westward, thinning clastic wedge … Read More