cragandtail

A crag and tail is a distinctive geological landform created by glacial erosion. It is formed when a large, resistant rock, known as a crag, obstructs the flow of a glacier. As the ice moves, it erodes the rock on the upstream side, creating a steep, rough face. However, on the downstream side, the ice is less erosive, and the debris carried within the glacier deposits material, forming a streamlined, tapering tail that extends away from the crag.

The orientation of a crag and tail is a clear indicator of the direction of ice flow during glaciation. The crag, with its steep face, is always found on the up-ice side, while the tail points in the direction of glacial movement. This feature is commonly found in landscapes that have been sculpted by past ice sheets, such as parts of Scotland, Ireland, and Canada. The size of crag and tails can vary significantly, from small formations to prominent hills that dominate the landscape. Studying these formations helps geologists reconstruct past glacial environments and understand the dynamics of ice movement.