Esker sediments can range in all sizes, and usually do not match the parent material where they are located. An esker river may transport the smallest clays to the largest boulders. The esker left behind by a glacier tells us a lot about the river it was formed by. When an esker is cut in cross-section, as often seen in gravel pits, different sedimentary layers are visible in an esker. Areas of finer sediments indicate much slower river flow, while areas of heavier sediments indicate a much faster flow.
Different sediments create different layers of the esker.
It is possible to find a silt layer with virtually no particles larger than sand, and 2 feet above find nothing but cobble and boulders. On top of this layer may then be nothing more than silt again. This sedimentation indicates the speed and force of the river during the time of deposit. The differences in the layer compositions may indicate seasonal changes and melting rates in the glacier.