Imagine a thick sheet of ice covering all of the upper United States. This ice was about a mile thick. It even covered the top of Mt. Washington! Two to three hundred million years ago, long before anyone lived in New Hampshire, glaciers came down from the Canadian borders. Slowly the glacier grew deeper and thicker, and covered the White Mountains. Part of it melted in the spring but refroze in the winter, and pushed further south in New Hampshire. New Hampshire was covered by a Continental glacier. The last glaciers melted away not much more than 15,000 years ago.

Glaciers scratched and scraped the notches of the White Mountains. Glaciers formed lakes and ponds that are now found throughout New Hamphire. Lake Winnipesaukee, in Wolfeboro, NH was formed by the glacier. Glaciers left sand and gravel in their path from the boulders they picked up. The sand and gravel are useful today. Every hill, swamp, mountain, pond, lake, and bog is the result of the glacier movements. Dozens of kinds of fish grew in the rivers and lakes formed by glaciers. Madison Boulder was dropped by a glacier. Lost River and The Flume Gorge were made by glaciers about 1,000,000 years ago.