Here is the history of geology around the lake.
The cliffs, granite ponds, and rock-strewn rolling slopes of the Lake Sagamore area were created by vast glaciers, pushing southwards from central Canada in sheets of boulder-studded ice over a mile thick. During the past 2 million years, four “ice ages,” each lasting hundreds of thousands of years, were briefly interrupted by warmer intervals. The current warm interval began about 11,000 years ago and is due to end a few thousand years from now despite global warming. The debris left by the melting glaciers includes the rocks, large and small, that litter the hillsides and were gathered by pre-colonial and