New York's New Finger Lake

Letchworth State Park, in western New York State to the southwest of Rochester, hosts what is referred to as "The Grand Canyon of the East". This canyon, and the sorrounding green of the park, can be easily seen on the satellite imagery of http://www.maps.google.com/ .

The Genesee River flows northward through the canyon and over several waterfalls, including one that is higher than Niagara Falls. So, this canyon inevitably gets compared to the gorge at Niagara and is presumed to have been formed in a similar way to this and the Grand Canyon in Arizona, which was carved out of the layers of sandstone by the Colorado River.

Today, I would like to introduce another point of view on the formation of the canyon at Letchworth State Park.

The canyon is actually one of the Finger Lakes of central New York State. But due to the elevation and slope of the land, the canyon is not filled with water like the Finger Lakes to the east, but rather a river runs through it.

These deep and elongated lakes were carved out of the rock by glacial movement from the north during the ice ages. The area must have been the site of very concentrated glacial activity because of the presence of the Niagara Escarpment to the west and the Adirondack Mountains to the east. These two permanent features acted as the sides of a "funnel" to channel a powerful glacial movement across the area where the Finger Lakes are located.

Just look on the map at the location and directional alignment of the canyon at Letchworth State Park, relative to the Finger Lakes located just to the east. The canyon fits right into the pattern of these lakes, and I am certain that it was formed in the same way rather than being carved by the river that flows through it. There was a glacial thrust channeled by the Niagara Escarpment, and going somewhat behind it, that carved this canyon out of the rock over successive ice ages and also the smaller Silver Lake to the west. The Genesee River found it's way into the canyon later.

At Niagara Falls, there is a valley in the rock layers which guided the flowing water to form the falls and the gorge, this is the valley that I named "The Niagara Valley" and is described in the posting on the Niagara natural history blog by that name. But at Letchworth, there is no such valley to guide the river which supposedly carved the canyon over time.

I usually do not like the word "impossible", so let's just say that it is extremely unlikely that the flowing waters of the Genesee River carved this canyon out of the rock at Letchworth, as is commonly believed. For one thing, water is not neat when it carves it's way through soil or limestone. Neither the Grand Canyon nor the Niagara Gorge are anything like neatly carved. But look at some of the photos on the article titled "Letchworth State Park" on http://www.wikipedia.org/ . In one photo, the rock wall of the canyon is so neatly cut that it looks like a cake cut by a knife. Ice is much neater than flowing water, and that is definitely the work of ice and not water.

You can see in the satellite imagery that the river actually meanders from one side of the canyon to the other, and that would not be the case if the river had carved the canyon.

Consider the sheer volume of water that carved the Niagara Gorge. The flow of water through Niagara is probably a thousand times that of the Genesee River, which supposedly carved this Letchworth Canyon. It is true that there was a lot of water around when the glaciers melted at the end of the ice ages, but that water supply lasted for only a brief time. There are other features around Rochester that were shaped by this rush of glacial meltwater, described in "Water Inlets Of The Niagara Escarpment Bulge" on this blog, but there is nothing anywhere else in the area like this canyon.

I think that we can safely consider the canyon at Letchworth State Park to actually be one of the Finger Lakes except that, due to the slope and altitude of the terrain, it is not filled with water like the other Finger Lakes, but rather a river runs through it.