The fossil to the right is a section from the root of a 100 foot tree which originated over 400 million years ago. It contains deeply pitted circular patterns, but its tree trunk differed having deeply grooved diamond patterns. It’s a very dense heavy fossil of petrified wood. Petrified wood forms when plant material is buried by sediment and protected from decay caused by oxygen and organisms. Then, groundwater rich in dissolved solids flows through the sediment, replacing the original plant material with silica, calcite, pyrite, iron or another inorganic material such as opal. This was a common occurrence in the swamp forests of the Carboniferous Period from about 360 to 300 million years ago during the late Paleozoic Era.
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The fossil to the left shows the leaves of these giant Lycopod trees such as Sigllaria and Lepidodendron preserved in coal shale. Their trunks were topped with these plumes of long, grass like leaves; in some cases resembling a bottle brush. Lycopods, such as these, had a relatively short life cycle growing rapidly and reaching heights up to 130 feet. They generated tremendous amounts of decaying peat, which after millions of years became coal and fueled the Industrial Revolution. More importantly, their decaying matter helped revolutionize Earth’s emerging forests by creating soil for trees to develop deeper root systems. This enabled new tree varieties to spread further inland without relying solely on wet or swampy habitats.
Botanical Names: Sigillaria and Lepidodendron
Common Name: Scale Tree
Division: Lycopod-iophyta (oldest vascular plant group, reproduced by releasing spores)
Class: Isoetopsida (plants with hollow quill-like leaves spirally arranged on a single, unbranched vein) ie quillworts, scale trees, spike moss)
Order: Lepidondrales (primitive vascular tree-like plants related to lycopods which are loosely grouped with ferns)
Family: Lepidodencraceae (has arrangement of spores on cones born on the shoots)
Genera: Sigillaria (possess deep lace pattern on trunk with bottle brush crown of leaves) Lepidodendron (possess deep diamond pattern on trunk with plume of grassy leaves on crown. Roots lack diamond pattern.