U-shaped valley
Grafton Notch reflects the glaciation processes carved by the Laurentide Ice sheet during the Wisconsin Glaciation episode. Notable geomorphology of the park includes U-shaped valleys, gorges, and esker. Erosional processes expose the unique bedrock composed of Devonian granite with pegmatite intrusions. Poorly sorted diamicton and stratified gravel pits indicate glacial and glacio-fluvial depositional processes at work. Additionally, these processes scattered erratics over the u-shaped valley floor.