Ausable Chasm
Ausable Chasm is a sandstone gorge and tourist attraction located near the hamlet of Keeseville, New York, United States. It is directly due west of Port Kent. The Ausable River runs through it and then empties into Lake Champlain. The gorge is about long and is a tourist attraction in the Adirondacks region of Upstate New York. It is fed by the Rainbow Falls at its southern extreme. Geological formation. Geologically simple, the Ausable Gorge was carved out of 500 million-year-old Potsdam Sandstone from the Cambrian Period. Since the end of the Pleistocene Epoch ice age  10,000 years ago, the movement and subsequent melting of glaciers created a series of caves and tunnels, which the Ausable River linked up and exploited on its journey to Lake Champlain. During this time, the headward erosion of ancestral Rainbow Falls led to its location today, where the visitor's center was built. The chasm has a continuous exposure of a section of Potsdam Sandstone more than thick, which includes a rare, mid-Cambrian Scyphomedusae jellyfish fossil. Some of the rock formations have been given names such as Cathedral, The Devil's Oven, Elephant's Head, The Flume, Sentinel Rock , and Table Rock. Tourism. In 1760, Major John Howe explored the chasm on ropes. Five years later, Irish settler William Gilliland wrote about the Chasm in his journal: "It is a most admirable sight, appearing on each side like a regular built wall, somewhat ruinated, and one would think that this prodigious clift was occasioned by an earthquake, their height on each side is from 40 to 100 feet in the different places; we saw about a half a mile of it, and by its appearance where we stopped it may continue very many miles further." Called by some the  Little Grand Canyon of the East, the chasm opened to the public in 1870.