Roches moutonnees are excellent glacial flow directional indicators. Ice moved from right to left, plucking material from the jagged region of the rock. Photograph courtesy of Eugene Domack, Hamilton College. Striations Striations are the smallest features formed by subglacial processes. They are scratches in the rock surface carved by materials held in the glacier as the glacier ice passed over the rock.
Striations are useful indicators of the direction of glacial movement.
Because the striation is a line, there actually are two possible directions in which the ice could have been moving. Striations on a rock surface. The thin dark lines from left to right on the image are fractures, or breaks in the rock. Striations on the peaks of the Transantarctic Mountains help us answer that question. These scratches, carved by debris tightly held in the ice, tell us that ice sheets must have been at least as high as the Transantarctic Mountains at some time in the past.