The Blue Mountain, or Blue Ridge region, is one of a series of near parallel ridges that run for tens of miles, and are equally likely to be called ridges or mountains.  

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The rocks of the Blue Mountain section include mostly sandstone, conglomerate, siltstone, shale, and some limestone.  These types of rocks tell us that where we are today wasn't always high above sea level, but was actually below sea level - imagine a basin, and the basin got filled up with dead sea life and dust from eroded rocks.  

What you are looking at, what lies before you, took hundreds of millions of years to form. The top level of our planet is called the lithosphere.  It is about 60 to 120 miles thick and is made up of individual tectonic plates.  These plates "sit" on the Earth's mantle and move around slowly - about an inch or two a year.

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The Earth's core is hot - about 10,000 degrees hot - the same as the surface of the sun.  This heat creates steam and molten rock - these push up and cause the plates to "slide" around or sometimes burst through as a volcano.

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When two plates collide, they either both push up creating a mountain, or one slides over the other creating a rise.

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Over the course of time, repeated collisions have created not just rises in the ground but sometimes folded over portions of ground.

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What you see before you was a major "demolition derby" that ended about 280 million years ago (it is still happening but less dramatically right now).

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So although we were once below sea level, all this underground demolition derby action raised us up, but rather unevenly.

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While all of this was happening underground, there were forces at work above ground too - wind and water were acting like sandpaper eroding or sanding down the ground.

Blue Mountain has a number of "gaps" - breaks in the solid wall of mountain.  Most were caused by running water - as in the Delaware Water Gap, some were too high up for the water to erode, but the wind was able to "rub" a gap into them. (All gaps are caused by the fact that the rocks in the gap area were softer than the rocks next to them and thus easier to erode).  Hopefully, at this moment, you are rubbing your head and thinking - "Ah, so that is why it is called Wind Gap".

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It is hard for us to understand how powerful water or wind can be in shaping the ground.  But consider the Grand Canyon - that huge and marvelous "crack in the earth" which was created by millions of years of water (the Colorado River in this case) running over the ground washing it away.

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Imagine putting a candy bar in the sink and letting water drip from the faucet on it.  Within an hour you would have a hole.  This planet had billions of hours to work on changing our ground.

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So the process that took place was the plates slowly pushing against each other and uplifting and folding the ground.  And then for a million more years wind & water eroding the ground, and then more uplifting and more erosion.

 

The Blue Mountains that we see in front of us were actually much taller millions of years ago - they have been wearing down.  About 14,000 years ago, the last Ice Age ended.  Our land had experienced a crushing, grinding action by millions of tons of ice "scratching" its way across the land.  The ice didn't really "retreat" - it melted away - imagine ten thousand Delaware Rivers or more, all melting at the same time.

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This rushing water gave the final "look" to our land.

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All this activity creates rock "dust" and also chunks of rocks.

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I've sometimes joked that in Eldred we don't have soil with rocks, we have rocks with a little bit of soil in between. Digging with a spade in Eldred is an adventure of pulling out various-sized pieces of shale and slate.  These rocks were left here, or date back, about 400 million years ago.

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Places where there are gaps - like Wind Gap and the Delaware River Gap can give you a better visual understanding of how our land is made of folded ridges.  On the Pennsylvania Extension 476, by the tunnel you can actually travel through 7 of these ridges underground.

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A bit further north and west of us, conditions created anthracite coal beds.  And a little bit south of us is the great slate "belt".

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Now, imagine tall trees and bushes growing - decorating the earth - and that is what you are looking at.

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Continue driving to the end of Correll Road.