Scherr Formation facts for kids

The Scherr Formation is a special layer of rock found in the eastern United States. You can find it in Pennsylvania, Maryland, Virginia, and West Virginia. This rock layer formed a long, long time ago during the late Devonian Period.

What is the Scherr Formation Made Of?

The Scherr Formation is mostly made of two types of rock: siltstone and shale. Siltstone is like very fine sand, and shale is a soft rock made from mud.

The bottom part of this rock layer also has some fine-grained sandstone, which is rock made from tiny sand particles. But as you go higher up in the formation, there's almost no sandstone. When you see this rock outside, it often looks like a light olive-gray color.

How the Scherr Formation Got Its Name

Naming Rock Layers

Scientists who study rocks, called geologists, often name rock layers to help them understand the Earth's history. The Scherr Formation was named by a geologist named J. M. Dennison in 1970. He named it after a place called Scherr, West Virginia.

Before this, a larger group of rocks was called the Chemung Formation. Dennison decided to split this bigger group into two main parts: the lower Scherr Formation and the upper Foreknobs Formation. Together, these two parts were called the Greenland Gap Group.

There is also a special part of the Scherr Formation called the Minnehaha Springs Member. This part has layers of siltstone and shale, and sometimes even some reddish siltstone and shale. Scientists think these layers formed from underwater landslides, called turbidites.

Where to See It

You can see a good example of the Scherr Formation along Highway 42 in Grant County, West Virginia. This spot is known as the "type section" because it's where the formation was first officially described. 39°11′45″N 79°10′48″W / 39.19583°N 79.18000°W / 39.19583; -79.18000

How Old is the Scherr Formation?

Scientists use different methods to figure out how old rocks are. Based on these methods, the Scherr Formation formed during the late Devonian Period. This was a time when fish were becoming very diverse, and the first land plants and animals were starting to appear.

Ancient Life in the Scherr Formation

Early Footprints?

The Scherr Formation is famous for a fossil called Thinopus. This fossil was found in 1896 by a scientist named Othniel Charles Marsh. He thought it was the earliest known tetrapod, which is an animal with four limbs that lives on land, like amphibians or reptiles. This would have been a huge discovery!

A Surprising Twist

However, later research showed something different. Scientists looked closer at the Thinopus fossil and realized it wasn't a footprint at all. It was actually coprolites, which are fossilized poop! In this case, it was likely the fossilized waste of ancient fish. So, while it wasn't the earliest land animal, it still tells us about the fish that lived in the ancient seas where the Scherr Formation was formed.

Images for kids

• 

  This image shows the Scherr Formation as part of a larger geological map of the United States.