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Brief Geologic History of Cascadilla and Fall Creek Gorges

Rolling hills, lakes, gorges and waterfalls of New York’s Finger Lakes characterize this region as one of the most scenic and geologically rich in the Eastern United States. The stunning gorges carved by Cascadilla and Fall Creeks are no exception.

A landscape shaped by water

Water in many forms has shaped the Finger Lakes landscape we enjoy today. An understanding of the events that shaped this beautiful landscape will provide the context for understanding how Cascadilla and Fall Creek gorges were formed.

How was the regional bedrock formed?

The layers of sedimentary rock exposed within the region’s gorges were formed over 360 million years ago during the Devonian Period (410 – 360 million years ago). Water in the form of a shallow, tropical sea covered much of what is New York State today. A vast mountain chain comparable to the size of the Himalayas was located to the east of this inland sea (The Appalachian Mountains are the remnants of this much larger mountain chain). Mountain streams carried sediments of sand, gravel and mud into the shallow sea and over millions of years, these sediments accumulated to form the thick stacks of sedimentary rocks we see today. The photo above shows ripple marks in the bedrock, which were formed along the shoreline of the ancient shallow sea.


Click here to read a more detailed account on the Paleontological Research Institution’s website.

How were the Finger Lakes formed?

Compared to fingers of outstretched hands, the Finger Lakes consist of eleven long and narrow lakes oriented north-south. Water in the form of glacial ice sheets formed the Finger Lakes during a period of many advances and retreats of glaciers known as the “ice age.” The Finger Lakes originated as a series of rivers that were bulldozed by the two-mile thick ice sheets. The most recent glacier that covered New York began melting away over 12,000 years ago and left behind the deep and narrow Finger Lakes with newly steepened valley walls. It was the formation of these steep lake valleys that “set the stage” for streams that flowed into these lakes to begin carving their gorges. The photo shows Cornell University on the hillside above Cayuga Lake, one of the central lakes, which is 38.1 miles long and 435 feet deep.

Click here to read a more detailed account on the Paleontological Research Institution’s website.

How were the gorges formed?

After the retreat of the most recent glacial advance, water of streams that flowed into the glacially carved Finger Lakes plunged as waterfalls over their steepened sides.  The streams began cutting into the bedrock of these hillsides, forming the gorges that characterize the Finger Lakes Region today, including Cascadilla and Fall Creek Gorges. The photo shows a view of Fall Creek Gorge looking east from the Stewart Avenue bridge.

Click here to read a more detailed account on the Paleontological Research Institution’s website.