Hurrican Mt weathered granite
The geology of the Adirondack Mountains is a monument to the shifting, irrepressible powers of the last ice age. Towering above New York's diverse landscape, the Adirondacks detail a history more than five million years old, when small alpine glaciers carved their way through the Northeastern United States. As the glaciers moved through what is now the Adirondack Region, glacial erratics - stones deposited by the glacier - were scattered across the landscape. Massive chunks of ice broke away from the glacier, and were buried beneath sand and gravel washed from the ice. As these ice chunks melted, depressions, called kettle holes, were formed. When the kettle hole extended below the water table, a pond was created. Many of the small, circular ponds you see while hiking in the high peaks began as kettle holes.
Over millennia, as glaciers carved away the landscape, mountains began to take shape. Unlike the Rockies and the Appalachians, the Adirondack Mountains do not form a connected range, but rather a 160-mile wide dome of more than 100 peaks. Although the mountains are formed from ancient rocks more than 1,000 million years old, geologically, the dome is a newborn. The Adirondack Peaks can be anywhere from 1,200 feet tall to well over 5,000 feet tall, and the 46 tallest summits above 4,000 feet are called the High Peaks. Although four peaks were later discovered to measure less than 4,000 feet, they are still considered Adirondack High Peaks.
The highest of them all is Mount Marcy, towering 5,344 feet above sea level. It is one of the most distinctive features of the Adirondack landscape. Mount Marcy is home to Lake Tear of the Clouds, the highest lake in New York State at 4,292 feet, and the source of the Hudson River.