The deposit created by a former meltwater channel or tunnel in glacial ice that was filled with sand and gravel is called an eskar. Eskars are long, winding ridges of sediment that can stretch for several kilometers and are typically found in areas that were covered by glaciers during the last Ice Age. They form when sediment carried by meltwater flowing under the glacier is deposited along the tunnel or channel, creating a ridge-like feature once the glacier has melted away. Eskars are important geological features because they provide insights into the history and behavior of past glaciers and the environmental conditions in which they formed.