Moss Island: Potholes and an Ancient Waterfall

Moss Island in Little Falls, New York, became an island by accident. When Erie Canal engineers needed to lift boats over a forty-foot drop in the Mohawk River, they built locks beside this outcrop of ancient syenite rock rather than through it. The island became famous for what the rock holds: glacial potholes forty to fifty feet deep, carved when a prehistoric waterfall once larger than Niagara roared through this valley.

The island covers fourteen acres and its oldest stones rank among the most ancient in North America. Designated a National Natural Landmark in nineteen seventy-six, Moss Island also draws rock climbers to its glacier-polished walls. Lock seventeen of the New York State Barge Canal, right next door, is one of the tallest locks of its kind in the world.