Glacial grooves, East Sister Island, Lake Erie, Ontario, Canada. The glacial grooves in this photo are roughly 385 million years old, and were created from the gouging action of ice flowing in the Lake Erie basin. Recent freeze-thaw activity has produced significant frost heaves, or raised blocks, within and beside the glacial grooves. —Source: Natural Resources Canada. Photographer: R.N. McNeely. Copyright Terrain Sciences Division, Geological Survey of Canada.

Lateral glacial abrasion on rock wall, New Zealand. Lateral glacial abrasion has smoothed this metamorphic rock. The flowlines indicate a downward direction. —Source: Tom Lowell's Glacier Image Database, University of Cincinnati.

Striated Graywackie, Yale Glacier, Alaska. 1997. Parallel striations and bedrock fracture trends (across the left side of the image) are clearly visible in this photo. —Source: Tom Lowell's Glacier Image Database, University of Cincinnati.

The glacial character of the surface shield at the Strait of Belle Isle is the effect of an ancient ice age about 1 billion years ago. The surface was preserved under a layer of sedimentary rocks.

The fine features in this photograph are glacial striations, or glacial scratches, produced where clasts (gravel and rocks) carried by the glacial ice and meltwater cut into the bedrock. —Source: Natural Resources Canada. Photograph by Lynda Dredge. © Terrain Sciences Division, Geological Survey of Canada.

Subglacial features, Ste-Marguerite, Quebec, Canada. Small outcrops have been polished by glacier ice and subglacial meltwater.The smallest features are striations. the deeper grooves, depressions and holes were formed from pressurized meltwater acting beneath the ice. —Source: Natural Resources Canada. Photographer: Lynda Dredge. © Terrain Sciences Division, Geological Survey of Canada.

Glacial grooves in rock panels, Churchill, Manitoba, Canada. The row of plants in the center of the photo follows a glacial groove in the rock. The grooves and striations (glacial scratches), along with other ice indicators, show the glacier flowed toward the front of the photograph. Source: Natural Resources Canada. —Photograph by Lynda Dredge. © Terrain Sciences Division, Geological Survey of Canada.