Wintergreen Gorge is a canyon located in Harborcreek Township, Erie County

Erie County, Pennsylvania

Erie County is a county located in the U.S. state of Pennsylvania. As of 2010, the population was 280,566. Its county seat is the City of Erie.- Geography :...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Pennsylvania. The canyon is 3980 feet (1,213.1 m) long and is situated along Fourmile Creek

Fourmile Creek

Fourmile Creek is an long tributary of Lake Erie in Erie County, Pennsylvania in the United States. It has a drainage basin of and is a part of the Lake Erie Watershed.- Course :...

 and is also directly next to the campus of Penn State Erie

Penn State Erie, The Behrend College

Penn State Erie, The Behrend College is a state-related public university institution and a Commonwealth campus of Pennsylvania State University located in Erie, Pennsylvania....

. It is 250 feet (76.2 m) deep at its highest point. Wintergreen Gorge was named for the plant, "wintergreen", that was commonly found in the canyon. The Bayfront Connector

Bayfront Connector

The Bayfront Connector is a , four-lane expressway that connects Interstate 90 to downtown Erie, Pennsylvania.- Route description :At the intersection of East 12th Street, the Bayfront Parkway becomes the Bayfront Connector and picks up the concurrency with Pennsylvania Route 290...

 spans the gorge over the Wintergreen Gorge Bridge

Wintergreen Gorge Bridge

The Wintergreen Gorge Bridge is a , steel, plate girder bridge that carries Pennsylvania Route 290 and the Bayfront Connector over Fourmile Creek and the Wintergreen Gorge in Harborcreek Township, Erie County in the U.S. state of Pennsylvania...

.

Formation

Wintergreen Gorge was formed 11,000 years ago by Fourmile Creek eroding the glacial debris

Moraine

A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have...

 left behind from the last ice age when the glaciers retreated 20,000 years ago. The glaciers left behind layers of sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 and shale

Shale

Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...

, which were more easily eroded by water than the underlying bedrock

Bedrock

In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

in the region.