In the first edition of “PEI: Permian to Present” we looked at what the Island’s famous red standstone tells us about the environment in which it was formed. Today, lets look at evidence it holds about the plants that grew here during the late Carboniferous and early Permian Periods!
At this time – about 60 million years *before* dinosaurs – the land that was to become Prince Edward Island was in the centre of the supercontinent Pangea and located near the equator. The climate was hot and dry for part of the year, before seasonal monsoons and flooding returned. This was a change from the hotter, consistently wet and swampy conditions of the earlier Carboniferous Period (or Coal Age) and PEI’s plant fossils record this transition.
Calamites (Photo 1) was a tree of the Carboniferous Period and an ancestor of today’s Horsetail plants (Equisetum spp). Growing to heights of 10 to 12 metres (30 to 40 feet), Calamites was able to reproduce both reproductively by spores and vegetatively by rhizomes, and so would have formed dense stands in the understories of Coal Age swamp forests. Like its much smaller modern-day relative, Calamites had hollow, segmented stems and branches which make its fossils fairly easy to identify; they’re relatively common around PEI’s coast.
Lepidodendron (Photo 2) is an ancestor of today’s Quillworts (Isoetes spp.) and Clubmosses (Lycopodiaceae Family). Also part of the Coal Age flora, it towered over the landscape with heights of up to 50 metres (160 feet) and diameters as much as two metres (6.5 feet) at the base. Many of the large stumps at the famous Joggins Fossil Cliffs in Nova Scotia are Lepidodendron, and I found my first PEI remnant of this tree earlier this year. The diamond-shaped pattern of its thick bark makes a distinctive fossil.
Another swamp-loving Carboniferous species was the tree-fern Pecopteris (Photo 3), growing to heights of 15 metres (about 50 feet) and diameters of about 1.5 metres (five feet). The cooling, drying climate during the Permian didn’t suit this species and – though it had existed since the Devonian, more than 100 million years earlier – it wasn’t able adapt. Pecopteris disappeared during the Permian, but its fossils can be seen in several places on the Island, and it’s one of my favourites to find.
The Permian climate was well suited for early conifers, such as Walchia (Photo 4) which would have resembled today’s Norfolk Pine (Araucaria heterophylla, often used as a houseplant). This tree was about 12 metres (40 feet) tall and a dominant species of the Permian landscape. There’s a forest of Walchia stumps across the Strait in Brule, Nova Scotia, and fossils are commonly found along our Island shores as well.
Taken together, the information about prehistoric climate and plants paints a picture of what our landscape may have looked like 300 million years ago (artist’s depiction, Photo 5).
Fossils are important records that help scientists understand how life evolved on Earth. If you find one on PEI, take photos, record the location, and contact archaeology@gov.pe.ca or Laura McNeil at Prehistoric Island Tours. Fossils are protected in this province and it’s not legal to collect them.
In the next edition of PEI: Permian to Present, we’ll look at a unique geological formation and I’ll connect you with some resources to learn more about our prehistory!
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