The Geology of the Mohawk Trail

By Natasha B. and Brittany W.

The wall at the Hairpin turn has seen a lot of action over the many years of its existence. Located along the Mohawk Trail in western Massachusetts, on Hoosac Mountain, otherwise known as Florida Mountain, part of the longer mountain chain, the Berkshires, which is part of an even larger mountain chain, known as the Appalachian Mountains that run from Georgia to Maine.

You can’t miss the large grey wall of rocks at the Hairpin Turn. Also known as an outcrop, this wall is one of the best examples of the unique geology you can find along the Mohawk Trail. The view from this wall is of a large valley with the Hoosac River in the north and the Housatonic River to the south. The Taconic Mountains are to the west with the Hoosic Range to the east. Both ranges eventually combine to form the Green Mountains in Vermont. Both of these mountain ranges average 2,400 feet from sea level.

It is hard to believe but over 500 million years ago these mountain ranges were flat land with a warm, shallow sea full of sea creatures, like coral and crabs and small fish. As the continents collided – particularly North America and Africa – the Berkshire Mountains were formed by the slow process of uplifting, bending, and folding of the earth’s crust. At one time – hundreds of millions of years ago, the Taconic/Hoosic Mountains were the tallest mountains in the world but erosion and weathering and thousands of years of glaciers wore them down. The main rocks found in the outcrops and bedrock along the Mohawk Trail are Berkshire Schist, Quartzite, and some Limestone.

The geology of the Mohawk Trail made it a natural foot trail for generations of Native people. When white settlers moved in western Massachusetts they adapted the trail to fit their need with their horses and wagons. In 1912 with the invention of the automobile a new road was built. Modern drilling and dynamite and nitroglycerine from the construction of the Hoosac Tunnel allowed the Hairpin Turn to be carved out of the mountain. Eventually the road was paved and today it remains a popular scenic drive – as well as a regular commuter road for our families. Check out these cool pictures of teh geology of the Hairpin Turn.