Fossil at Ferncliff

Rock, path, with fossil at Ferncliff (photo by Kate St. John)
Rock with hashmark pattern across it (left to right) at Ferncliff, Ohiopyle (photo by Kate St. John)

15 July 2015

Years ago when I first hiked the Ferncliff Trail at Ohiopyle I was puzzled by this pattern on the rock beneath my feet.

In those days there were no interpretive signs nearby so I tried to make sense of it as best I could.  I decided it was a motorcycle track, but I couldn’t figure out how the vehicle had gotten there and why it had run from the cliff into the river.

Duh!  Motorcycles don’t leave tracks in rock.  It’s a fossil!

Fossil at Ferncliff Peninsula (photo by Kate St. John)
Fossil at Ferncliff Peninsula (photo by Kate St. John)

This Lepidodendron is one of six kinds of fossils found along the river’s edge now listed on an interpretive sign as: Cordaites leaves, Lepidodendron scale, giant Calamites, Psaronius, a giant dragonfly and Sigillaria.

Though I’ve seen the other ones this is the fossil I like the best.

Lepidodendron was a tree-like plant with scales on its trunk that grew as high as 100 feet tall.

Drawing of Lepidodendron by Eli Heimans, 1911 (image from Wikipedia)
Drawing of Lepidodendron by Eli Heimans, 1911 (image from Wikimedia Commons)

It lived and died in the Carboniferous (coal making) era.  If the tree had fallen in a swamp it would have become peat and then coal, but it happened to fall on sand so the patterns of its scaly trunk were preserved in rock.

Not far away is one of Lepidodendron’s last living relatives: Lycopodium or groundpine. Only 6-12 inches tall, it provides a visual hint of its ancestor’s appearance including the scales on its trunk and branches.

Lycopodium (photo from Wikimedia Commons)
Tree Groundpine, Lycopodium dendroideum (photo from Wikimedia Commons)

The past and present are near each other at Ferncliff Peninsula.

(fossil photos by Kate St. John. Drawing of Lepidodendron and photo of Lycopodium from Wikimedia Commons; click the images see the originals)

3 thoughts on “Fossil at Ferncliff

  1. Nice article. I haven’t been to the trails at Ohiopyle yet, but I’ll be looking for these. Thanks.

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