Glacial till is poorly-sorted sediment that has been transported and deposited by a glacier. Till is a mixture of clay and rocks ranging in size from sand to large boulders and can get cemented together as seen in image A. Image B depicts a hanging glacier that formed high on the valley wall as snow and ice accumulated and failed to descend with the main glacier. Image C shows a landscape of the glacial valley that was formed by erosion during the retreat of the glacier, as well as the trimline highlighted in C-1. A trimline is a visible boundary between weathered and un-weathered bedrock that marks the previous height of the glacier.